I'm having the same/similar problem. I am on PS5 and can't add either of two friends on PC (nor can they add me) on the PS5. When logged into Origin we can see that we are already friends, it just isn't showing on the game.
Also, we tried setting up portal servers to join and found out that we aren't able to see the same Portal games (we have completely different lists when browsing or searching). We get no results searching for each others' games. Cross-play is enabled in the settings for the server/experiences, as well as in game settings on both sides.
I saw this as a known bug:
"We're aware of a unique situation where accounts that have access to Battlefield 2042 across multiple platforms may cause Cross Play Friends to not appear"
I had my EA and Playstation Network accounts linked up when I had a PS4 and played previous Battlefield versions. Given that PS4 and newer PC cross-play is not supported, I suspect it may be related to this. I tried un-linking and re-linking my PSN account in my EA account but that didn't fix the issue.
I hope they can figure this out soon!!