You need a Mac or Linux box with internet connectivity with a domain pointed to it (You probably could do it using dynamic DNS too.) I don’t know how much power it needs, you might be able to get away with something like a Raspberry Pi.
You can either run it on your own hardware, or host a server with something like Digital Ocean Droplet, A2 Hosting, AWS, Azure, etc.
You would have to use the Open Source Matrix clients like Element or SchildiChat instead of the actual Beeper App, but you would be able to use the Beeper bridges.
My wife has the Samsung Flip 4, and it’s pretty nice. The screen comes with a screen protector on it, and you have to replace it occasionally, because it will start to delaminate around the crease.
For my wife it was a way to have a phone that fit in a small purse without any issues. It works well in that scenario.
I don’t know how well it would hold up to significant dust and debris.
I’m currently replaying Half Life (actually Black Mesa). I usually replay Half Live 2 every couple of years, and Portal 1 and 2 every year.
I played through Doom and Doom 2 a couple years ago, and I play a web version of the C64 game Impossible Mission at least one a week.
Clearly I’m old and nostalgic.
Coming to it from Crash Bandicoot, there was just something off about how Mario 64 controlled.