It seems that in both instances, you might take a step backwards before progressing further in your riding.

By this I mean that learning to ride with clipless pedals can feel like a regression since it adds another element to learn to the skills with which you are already comfortable.

In some ways, mostly social stigma, the same might be true of cycling shorts. You might get them on and then feel less interested in going out in public.

However, it is possible that neither of these common reactions happen to you.

My advice, if you are willing to make the investment of time, money and effort, go for the bike shorts and clipless pedals/shoes.

If at any point an "upgrade" is causing you to ride your bike less, get rid of it and maybe try it again later.

Lastly, cycling can be taken far too seriously... don't forget to have fun.
Good luck.