I was gonna say the same thing since I also just copy-paste URL which works fine, but I was never able to find a way to remove shorts. I just tried OP’s instructions for that, I am so happy to finally have no shorts in my feed!
I’m actually surprised that YT is not forcing the shorts on everybody (yet).
I would hate being constantly pinged by those but hey, most of the channels I’m subbed don’t rely grind the algorithm and just opted out from that. 