Sounds horrendous and I do really feel for you. The annoyance of those drop outs during zoom calls or lessons must be so frustrating.
Good luck, let us know how you get on.
I had this exact problem. I SEEM to have sorted it by replacing my socket plate with newer one where the phone and adsl lines are separate so don't need a filter.
So far there doesn't seem to be any dropouts. Been a couple of months so far.