loss of wifi and bluetooth

i have an iphone 8+ that has been very reliable. lately, wifi stopped working. in fact the wifi button is always in the off position and won't slide on. bluetooth doesn't have a button any more just the "i'm thinking" spinner where the on/off button is. it does this whether in airplane mode or not.

i've upgraded IOS. i've done reset network settings, reset all and erase all data (starting from OOTB). nothing seemed to work.

i opened the phone and removed the wifi bluetooth antenna - and amazingly the wifi started working, albeit for just one day. put back the original wifi and bluetooth antennas and same result (nothing). put in different (known good) wifi and bluetooth antenna, again, same result (nothing).

any thoughts on what to try next?