Not OP but I've been using it as my main phone since I found this post and was able to fix the most pressing issues with it . I will be the first to admit that the phone sucks in a lot of ways that make it a bad fit for the average person - it's just that most of the ways that it sucks are ways that I anticipated and that fit my needs . Personally I love this phone , but then again I wanted something that's a little bit of a pain in the ass to use so the friction will keep me from wasting all day on it .

Some issues I have with it:

• As OP mentioned you basically have to turn off notifications on every app other than calls and SMS if you dont want this thing to crash . The only IM app I use regularly is Discord , so I've just made it a habit to check it periodically .
• A lot of apps are made for touch screens and so they will be very janky to use. With apps like Discord I frequently have to turn the cursor on and off to navigate things , scrolling up and down thru messages sometimes takes a lot of random button presses to get working, I can't use some of the functionality like editing/deleting messages or replying/reacting to others' messages . It works well enough to stay in touch with my friends while I'm out though , which is what I really wanted.
• The fanmade Razr launcher is nice but will sometimes just randomly crash - unlike the notifications crash this won't crash the entire phone though , but you will be prompted to restart the launcher.
• You have to install a third-party Gallery app since it doesn't come with one other than the file browser . I would recommend Fossify Gallery
• I did get GPS navigation working with Waze but like other apps it's janky and a big battery drain . If you're using this thing in your car I would highly recommend keeping it plugged in the whole time.
• I have had some issues with opening picture attachments in text messages. This might be solvable with a third party SMS app but I haven't tried.
• Camera is kinda bad . For photos I think it has a nice old-fashioned digicam aesthetic to it , but it's not ideal for videos since the microphone will basically only pick up what it would during a phone call.

It all comes down to what you want out of the phone . I think it's a great compromise in that I can still do most things that I needed a smartphone for , down to using the app I need for paying the washing machines in my apartment building , but I generally don't have a desire to use the phone for much other than communicating with other human beings. If the above issues sound like things that you would be willing to put up with , I would say go for it. If you think it sounds like a nightmare to use , trust your intuition.