What you do with your phone should have very little effect on other users.
5GHz allows for more connections ~ so wifi on 5GHz
Bluetooth running on 2.4Ghz as it always does is then quite separated.
However noting other issues it may just be a loose module or internal dampness causing a number of things.
Are you happy to dismantle and check the innards a little ~ within warranty allowances. If so see the iFixIt guide ~ up to step 7
See