Same has happened to me I'm still waiting for a fix however I logged in to my show account only(current session) and was able to click on the mlb 21 game and that took me to where I can atheist see the stubs and cards I had prior to losing progress and took screenshots of it

mottasmotor_PSN
@mottasmotor_PSN
Posts
-
-
I received a response saying they are aware and working to resolve so maybe there is hope
Linked account on The Show website; lost game progress
PSA: Don't Link both PS and XBOX Accounts!