Thank you everyone for trying to help fix the issue!!
I just found the solution by switching back and forth between several options in the Serato preferences. Switching from 33 RPM to 45 RPM and then back to 33 RPM fixed the BPM indicator to be all the same now. Still seem to have some issues with the beatsnap not syncing songs 100%, but I have to check if that’s for some songs only (reanalyze, edit beat grid,…).
(BTW: my player already came with Engine DJ 3.1.1 and factory reset did not fix the issue)