My laptop isn't good enough for the Overhaul mod and I don't want any gameplay mods.

Is it fine to play the vanilla game?

Yes

Yes as in its fine to play the vanilla game or yes it's really bad without mods?

Of course it is still fine.

And even if your laptop cannot handle the MSGO overhaul, that doesn't meant you still can't use many visual enhancing mods.

If you can run Morrowind, then you can use almost any texture replacers with no problem.

edit: the Overhaul has a setting for weak/old computers.