T3 T4 Time Outs

I am struggling to resolve my T3, T4 time out issues. My connection gets disconnected randomly. Almost 3 tech visits have happened over the last year and every one says the signal is fine when checked at that point of time.  I have tested with a couple of net gear modems which seems to work perfectly fine at my friends but fails with T3 and T4 time outs at mine.  With WFH the new norm, am really frustarted. As a last ditch effort am seeking to replace the cable line to my house from the xfinity box down in my apartment building. The request was strangely deflected by xfinity to the rental property management.