but Congress would rather ratify Roe v. Wade (which they should) into law than see marijuana legalization.

I acknowledge that you said "they should", so that's good, but I have to question why you even thought to use that example? In what world would they not prioritize that? Even if they were all pro-legalizing marijuana, Roe is a decidedly more important issue.

Realistically they would just do both things at once but if we're going to commit to this hypothetical where they can only do one thing at a time, yeah, it goes without saying protecting women's reproductive rights (that were only recently taken away) is more pressing than pot.