Eh, I don't know about that. I'm predominantly online because the offline AI is terrible and ML is barren, but even so I don't use the major online modes.
For 1v1 I use the friendly match lobby, using custom teams loaded in from Edit mode > Master League > Save team data. That's as part of a bespoke league setup with 100+ managers, each having individual teams and a transfer market. This kind of online play may well not be supported, or may not be possible until gone February, who knows. And we don't know if the dedicated servers will carry across to things like friendly lobbies (I suspect not).
For other online play, I mainly play 11v11 matches using the team lobbies. So custom players made using BAL mode > load BAL saves into team lobbies when selecting individual players. Then play against other teams in a large FUMA league. That's looking even less like it will work with the changes they've made.
The only other thing I dabble with is myClub co-op with a mate, where we train youth prospects and play FUMA against the sweatiest people all with 100+ OVR players in their squads. (That's pretty thankless..) Of all the ways I play online, that's probably the only thing that would be supported any time soon, and it's my least favoured of the ways I play.
Then there's more interesting things about the reaction. PES fans across Europe and LatAm have been rarely united in opposition to these changes. Many of the myClub/streamer crowd think the gameplay will be simplified, and they hate the idea of playing vs mobile AND they hate the idea of playing vs PC (because they fear it will be so much easier for cheaters to use PCs to void/null games when they're losing).
And if you're an online player who does myClub or Divisions, you have other reasons to lament the changes – the 1-on-1 focus, the lack of team ID. Not all online players agree, but I think PvP games are improved when there is good AI – the kind of AI offline players tend to prefer seeing in the game. Personally, when playing other people, I fucking loathe that the midfield is bypassed with one pass every time. Or how big the pitch is, etc. Things like this mean people play in really unrealistic ways, and it fails to resemble football to me. That's not good for the PvP experience either, at least if you're the kind of player who cares about realism.