Hi! If you really rely on a working smartphone, simply avoid any kind of beta software at all. There is a reason it called a beta "test", to figure out bugs like this - it's more or less expected for things to not work. That's the reason why I personally stopped participating a few years ago, because I actually rely on the phone.
No offense, but I also think your whole post is very poorly structured for providing feedback and I had sort of a hard hard time reading it. I will try to comment on some:
Proximity Sensor: You mentioned it doesn't work well on OS 4.0 beta and also had issues on previous (stable) versions. Personally in two years of use I never had issues with the sensor on NP2. It might be very well related to your phone directly. Do you have a screen protector applied? There are screen protectors out there which can mess with these sensors - there is a reason why, a number of years ago, some protectors had actual cut outs for proximity sensor. Also dirt and skin grease, often in combination with a screen protector, can mess up the proximity sensor. Try to fully clean your screen, remove the screen protector and see if it has improved. If not, it might very well be a hardware related fault which needs to be fixed by repair.
Signal Quality: Did this happen also in prior versions? I remember a while back, I think it was with OS 2.5, there was a bug causing the device to stick to Edge mode (the "E" you are seeing) and it needed a restart to get the cellular system back working again. However it was fixed long ago. Is it really worse in common places you frequent than OS 3.0?
Camera: Let's face it - the NP2 never had great image processing, it was always inconsistent and felt poorly optimized. I had high hopes they'd bring their new TrueLens 4 (or at least 3 from 3a) to the NP2 and finally improve the inconsistent camera situation, it would have been a nice farewell gift for the very last major update of this device. Do you think the OS 4.0 beta actually degraded the overall quality compared to previous versions?
With all that, keep in mind the actual way to report bugs is from the device itself, by going to Settings -> System -> Feedback -> tap on the little "Feedback" symbol. This way, the reports will surely reach the developers, while here, on the Nothing Community forums, it can easily be missed. While Nothing staff is actively reading here, they don't spend all day long checking every single topic.
They opened an official beta feedback thread gor each device, the one for NP2 can be found here:
https://nothing.community/d/43343-phone-2-nothing-os-40-feedback
They created these to have a better overview of feedback for each specific phone.
