Brief description of said problem for me:
Can't play against friends in FIFA or FUT, no matter what we try, we can play co-op seasons no problems, but not friendly matches, after invite the game tries to go to pre-match screen, but it will not load fully and after a 5-10 seconds it just displays this message: "your opponent lost connection" or something along those lines.
Note: with this particular friend, we used to play friendlies no problem, but somewhere during fifa 19 it stopped working without me being aware of any changes in our hardware, both in networking part or otherwise and since then it's always the same problem. Also, no problems in playing any other part of the game online for both of us.

I understand that it might be some kind of problem on our ends, even though we did played friendlies no problems and it just stopped working, but still, any information on what could be causing this problems, so maybe we could try and make it to work somehow. When I check here at Answers HQ there are topics each year about this, some have suggested solutions, but most of the time it won't help.

Anyway, my thoughts are that, maybe, some development teams that are responsible for this part of the game must be aware of such occurrences and even if it is our problems, maybe, they can suggest what area can cause such problems and maybe point us in the right direction about solving this on our own.

It's very hard for me to understand how can I play thousands of matches through out a year with people from all over the world, but can't play against some specific friends, there must be something about some part of this game that can cause this problems, also because no similar problems happening in any other game, at least nothing that I'm aware of, so how this can't be solved between EA, PS or whoever and whatever.