THANK YOU so much for this. I'd spend some time researching how to disable YouTube shorts only to come to the conclusion that I had to use a different client (I picked NewPipe, but faced frequent issues with playback and I ended up having to click out to YouTube 90% of the time anyway)

I've disabled YouTube history now and it's almost exactly what I'd hoped for. Shorts are disabled, no 'feed', no suggestions, just my subscriptions. I owe you a beer.