First it would be better to write names of some maps which are crashing game or even better ask your friends to try them.

You can also read through topic about some Workshop maps crashing game in Bug Reporting section:
https://psteamcommunity.yuanyoumao.com/app/252950/discussions/3/3427822455452819600/

I know this is too late but i am still commenting in case someone still suffering from crash when opening workshop maps.
The reason is due to missing texture files.
Just download texture zip folder and copy paste in CookedPCConsole folder in rocket league.

im having these problems, im missing over 14 different files n i keep crashing any idea on how to fix this