My video is kinda long and unedited, and I don't imagine it'll be too interesting for someone to watch from beginning to end, also it's quite unstructured and full of me just rambling, so this post here will be like a summarised and a more organised version of it.
I am also aware that we already have a thread dedicated to dumbphones, but I thought it would be better to make a separate thread, 'cause I have a lot to say.
I'll link the video at the end of my post.
Let's begin:
Info
- The phone is a Sonim XP3 (or XP3 Plus, I'm not even sure myself)...
- It's not a "proper" dumbphone, as its operating system is based on Android 11, but it's been quite significantly "dumbed down" and simplified, and, best of all, de-google-ified... no Play Store, Play Services etc.
- It's rugged, and really strong. Can fall from great heights and not break, it's also waterproof.
- It also looks incredibly cool, and makes me feel cool for having it, and pulling it out and flipping it open and putting to my ear... Haven't done that in a while...
- I feel like I've cured a smartphone and dopamine addiction with it, as now I'm not looking at it at all when I'm bored, and only using the phone when I get a text or a call... I'm fine with being bored and not doing anything and not just constantly having my brain overstimulated
I'll start from the least problematic towards the most:
- Interface is kinda limited, which may not necessarily be a downside/issue
- You can't organise apps (even though this is a more minor inconvenience). I like to organise my apps in folders, but here I can't. It's not a big deal, as phones back in the day couldn't do that as well...
- It has no appstore, and no appstores are supported. The only working way of installing apps on it is by using your computer and sideloading them with adb - which may not be an issue for some people
- Only supports 4 languages (English, Spanish, Korean and Chinese), no other. Both the interface and the keyboard. This is not a big deal for Anglophones but good luck if you're from other parts of the world... I cannot type special characters unique to Serbian language + the majority of my contacts are written in Arabic, so I gotta either search by number or rename them to the Latin alphabet, which is too much work...
- It requires a lot of force to open the case, and sometimes I'm afraid of breaking it. Unfortunately, you'll, most likely, be opening it often...
- That mini screen which is seen when the phone is "closed", often doesn't work. Sometimes it shows static, and sometimes it's just black. It happens quite often, even though it usually starts working again after a couple minutes. It's inconvenient when you wanna just quickly check the time.
- The keyboard is not 100% reliable, sometimes it registers a keypress twice, and sometimes it doesn't register it at all. Significantly impacts typing speed. My job depends on sending a lot of text messages and making a lot of calls, and I've had a lot of issues at work, I've made my job way more difficult and definitely got to points where I regretted getting this phone.
- Battery life - every single review of this phone I found online says that the battery life on this phone is crazy and can last up to 4-5 days with heavy usage... Mine lasts for only a couple hours when Bluetooth, Wi-fi, Hotspot etc. are enabled. If I disable everything and only keep data, it is able to make it through the day, but barely... I'm not getting the crazy battery life they're talking about... Maybe I got a faulty one? Cause mine can't last a whole day... it's worse than average Android.
- If the phone battery gets to 0%, for some reason you have to physically remove the battery and put it back in, before it can start again... Even if you plug into a charger, it will charge (even though the phone won't indicate it in any way), but you cannot power on the phone until you remove and reinsert the battery... I'm not sure whether this is an issue with this phone or just mine in particular though...
- Major issue / possible game breaker - it doesn't have a touchscreen, even though most apps expect it (even some system ones), so it's close to being unusable without a bluetooth mouse. There is no issue in a phone having no touchscreen, and relying on physical buttons only, but when it's done well, and when apps are adapted to it...
- Another major issue - sometimes it will just randomly switch off, and not be able to start without reinserting the battery (same like when the battery gets to 0%) - even if the battery is full or charged to any percentage... The first time it happened it almost gave me a heart attack as I thought the phone died. In these 2 weeks it happened about 3 times so more often than once a week. The issue is that it happened when I wasn't home, and I didn't have a screwdriver or any tool near by to be able to open the case and remove the battery (now I learned not to tighten the screw on the back too much, so it's openable with a fingernail), so I was left in a tough situation as I was supposed to make a phonecall and I also had a client at work waiting for me... Unfortunately I've been in a bunch of tough situations due to this phone, as it is very unreliable. Sometimes also I wasn't getting message notifications, and even calls, as one time my mother called me and I didn't get a call, not even a missed call notification, and it was just telling her that my phone is off...
- I still use it as my main phone, and am trying the best I can to adapt to it. I don't have an issue with dumbphones in general, but this particular phone is just.. not very good.
- Maybe in the future I can get my hands on a better one, but for now, I'll keep trying. I'm praying I don't revert back to a smartphone.
As for a conclusion: I definitely don't recommend this particular model. There is a ton of different amazing phones I found during my research, but sadly, none are available in here.
There are many different phones, such as Kyocera, Emporia Touchsmart, Sunbeam, megalife zen f1, alt? mive? lg wine, lg folder, aspera? ttfone, vortex, and many many more feature flip phones, which support modern messaging apps like WhatsApp etc.
There are also many different "types" - some use just regular, stock Android (which I'm not the biggest fan of) - others use some types of systems which were based on Android but with Google stuff removed (like mine). Some use other types of systems, which are not based on Android at all... There are many different roads one could take...
For the end, I'll recommend this resource for anyone who wants to find a dumbphone which matches their needs: https://www.dumbphones.org/
I cannot access Neocities at the moment, but when I am able, I'll take screenshots of how our websites look on it. They look quite fun!
And also, if someone wants to see me rambling for 23 minutes and 40 seconds, here's the original video I made:
I'm sorry it's hardly working out for you, that is a ton of downsides, especially since you went to such lengths to get it and it looks so cool and well built. It's kind of an interesting device to have around nonetheless but yeah that would be tough to daily drive. 
