This may not apply to you, but the way I consume YouTube is by turning off history and subscribing to the creators I want via RSS. That way I seldom even remember Shorts exist; they simply do not appear for me.
If that wouldn’t work for you, consider removing the app and accessing YouTube via the browser. I would be surprised it there’s not an extension or blocker which can disable those.
I do this as well but find it a bit of a pain to add/remove sources since YouTube doesn't offer any easily accessible RSS feed. Wish there was a way to sync subscriptions with the YouTube account but at the same time I would never allow third party access. I refuse Google login on third party sites.
If that wouldn’t work for you, consider removing the app and accessing YouTube via the browser. I would be surprised it there’s not an extension or blocker which can disable those.