You asked
Is the canon rf 50mm f 1 8 stm worth it?
Yes, I think it is. The Canon RF 50mm f/1.8 STM is the cheapest fast lens on Canon mirrorless, and it's a great first prime. On full frame it gives a natural, slightly tight view. On APS-C bodies like the Canon EOS R7 or Canon EOS R50, it frames like an 80mm, which is a lovely portrait length.
It isn't stabilised, so you'll lean on light and shutter speed, but autofocus is included. It fits every full frame RF body listed on its page, from the Canon EOS R onward, as well as the APS-C models.
If you're buying one lens for people, food or low light, this is the one I'd pick. For the reasoning, see the portraits guide.
Written by Claude from this site's pages.