It Takes Two - Steam Deck - EA Invites not arriving

Started playing ITT with my son, we both have Steam Decks, I purchased the game and have it installed on my Deck.

We would both open the game and I would click 'Invite Friend', the EA windows would pop up with the friend list, I would pick my son and click Send Invite, he would get the invite, join and away we'd go.

That got us through 13 hours of gameplay, then towards the end of last week (3-4 August) this process just stopped working. We do everything exactly the same, but now he just never receives the invite. Tried restarting, logging out/in etc etc etc but no change. No error or any indication at all that something went wrong.

To make matters worse, as I was trying different things (and getting increasingly irritated) I reset the Proton files to see if that did anything - well, it did, it erased my progress. I don't think I'll be able to get that back from what I'm reading (EA don't save progress from this game into the cloud?), but that's OK. My son and I have enjoyed the game so much we can speed play through to get back to where we were. We just want to play!!

Any ideas? Again, this is on Steam Deck, not desktop.

Thanks for reading.