a week ago
Friday
Most likely it seems possibly more hardware issues compared to any possible software side problem. You may get it checked from service center for thorough check-up.
You can try the SMMI test from Calculator > .12345+= Do the hardware tests as per your requirements. You may find something from results. But in your scenario all the problems you mentioned this SMMI hardware test the results may not have possible data in results that can track further possible troubleshooting or diagnostics.
Extensive test can be performed at service center to address your concerns with possible solutions.
Saturday
Thanks for the info on the smmi test, I never knew about it, however the issues haven't been resolved permanently. I did the test, most of the results were positive, I booted my phone in safe mode and I still had issues. The problem comes and goes, for example as of right now I'm not experiencing any issues but up to yesterday the phone was messing around again. It seems really random and I can't determine what causes the problems.