Think Wilder touched on conditioning and athleticism in a recent interview, he said it was one of the biggest lessons we've learnt in the PL. I'd say you can tell we've at least tried to address this in our recruitment. The clearest example of this was Norwood -> Berge, going from someone whose running ability was his weakest point to someone who could cover lots of ground with ease (obviously you could argue he lacks strength, aerial ability etc but you could see the intention). Also Burke who is all about his physical attributes - much quicker and much stronger than the man he replaced. We've also looked to reduce the age of the squad which will help in this regard as well. I wouldn't say Brewster's best attributes are physical but he's at least quicker and younger than Sharp. The same with Lowe - not quick necessarily but quicker than Stevens.
I mentioned it ages ago but I still wonder whether we put in too much work during the first lockdown. As a team who haven't been able to rotate over a period of years, a lot of our players now look knackered. It's easy to say Lundstram's stopped trying but he's also played a lot of games and would've had a break with a bigger squad.
Overall though, even allowing for tiredness, injury to our most PL-like player from a physical point of view in JOC etc, we do look physically small and somewhat lacking in pace and strength as a squad (we have done for seemingly forever - well before CW's time).
It'll be less of an issue next season but will need rectifying when we're back.