Disclaimer: obviously I don't want to get relegated
Everything you said is true, but I think there is another side to that coin. Burnley, who had a significantly worse squad than us, got relegated a few seasons back then absolutely romped the Championship under Kompany. Newcastle had a great time down there under Benitez and came straight back up.
De Zerbi with, say, 60% of our current squad, our best youngsters, and a few signings, would be very very competitive in the Championship indeed. I'm not gonna get all cocky and say we'd definitely walk it, but we'd be in an extremely strong position compared to the teams that have gone down and struggled.
I think if we go down and come straight back up it will be remembered by fans as one of the most fun, memorable seasons in a long time especially in the wake of 2 years of constant losing in the league. A new dawn, integrating youth, winning games, playing teams we never normally play, etc.
Whilst I ( and a fair few others on here ) genuinely loved the 77/78 season ( although it was incredibly nerve-wracking at the end and we only claimed 3rd spot on GD on the last day ) ; I fear it wouldn’t be quite so enjoyable this time around ( should the worse case scenario happen) .
I hope you’re right btw ; but for me , for now at least, relegation is something to be feared and avoided; much like spending a nine month holiday in a remote unheated cabin in Siberia , in winter, with only Liz Truss and Paul Merson for company .*
( Other less extreme analogies are available ; but you get the picture ).