Why does manjaro set nosuid on local drives?

That stupid “feature” ruined my steam installations after I had to replace my manjaro installation after a crash, I don’t see how that is useful in a normal user environment, server fine but not desktop

You probably are on the wrong (thinking/assuming) path here.
… this could be an example of an xy problem - where you think you know how something should work
but where there is an entirely different approach required to tackle your problem

… what is it that you want to do - that doesn’t work like you expect it to?
What you think it is the reason for it is … secondary.

I wanted to retain my steam game installations and just play them, now I’m having to reinstall and start from scratch because manjaro decided a local drive was not mine despite me being the only user on the system, it should’ve defaulted to not setting nosuid and set myself as the owner and group for all the files inside while preserving the file permissions of the rwx as they were, it was not until after trying to take back control of the files and directories and finding manjaro was resetting the owner and group to nobody and not permitting me to do a basic action that I thought that the rwx had been messed with so I reset those globally (because there is far too many for me to be manually setting), when that failed over and over, only then did I think of checking the mount options, no normal user will think of those options first, this is guaranteed a major reason why peops still go with windows, because they have horrid first experience of trying to use their own files only to find they have no access, get lead down the wrong rabbit hole when the google the problem and end up screwing their own data over

well, you (still) didn’t say what happened, what you did afterwards …
for instance:
what the file system types are that you are trying to re-use …

… with different users come different user id’s (possible on a new or re-installation
user names won’t match anymore with the id’s

… it still does sound like more of a rant than a query and question on how to deal with whatever your course of action got you to

… I won’t be here again until maybe at least one whole day from now - maybe more

anyone else that might have some input on this is encouraged and appreciated …
I just wanted to get this going … despite it’s apparent negativity

Well the filesystem was btrfs so there shouldn’t have been the no write/no execute behavior that fat gives for whatever reason (that’s another dumb decision for desktop side), as far as what happened goes when I tried to launch the games they just refused to boot because they couldn’t get access to my files and when I finally got the access back they recalled that prior state and refused to boot anyway, I had no choice but to uninstall (which deletes my saves as well - did not realise until too late) and reinstall to clear the recalled state, all that happened because desktop manjaro did not simply assign correct ownership on local drives after 1st finding them upon a new installation

with btrfs you are quite well into the “advanced” territory.
I have NO experience with that (nor do I wish to have - zfs, maybe. btrfs … nahh …)
So: since this is re btrfs:
I’m out - because I have ZERO experience with it.