I think your argument is really fair as long as the guys in the 20 man squad perform to a level. Let's address the elephant in the room here. Since 2019, Spurs have been mostly bang average and we've had loads of players that have been part of that mediocrity. Within that, we've had perhaps 2 decent seasons. Even with Poch, a player like KWP deserved to be in the squad. Trips and Aurier were performing terribly but if they were fit then they were selected. KWP even came in got 3 or 4 assists in a game and still got dropped.
I think KWP is a great example as he fits your criteria of "nowhere near the required level". I think we all felt he wasn't going to be that top 4 left back we required after watching the club struggle to replace Walker. That doesn't mean Tripper shouldn't have been told to sit games out as he struggled with all those abductor issues. He was terrible at times, and arguably Aurier was worse. Were they the required level? Not for me.
This stuff is really subtle. I couldn't be happier to see Japhet wearing the armband for Sheff Utd and becoming the outstanding centre half in the Championship. We gave him 27 appearances in a 5 year period. Yes, he had injury issues but he was never treated fairly. There was no level playing field with guys like him and Davies. There was just bias to the older player.
This is why RDZ will need to be held to account, like all managers, on statements he makes. I'm hoping the biggest thing we're learning with RDZ is how he judges players. He was talking this weekend about players wanting to play for him and basically leaving the club if they don't want to. The first thing he needs is their total buy in and trust. Then he can pick through the ability and suitability part for his system. So if LWB or Moore want it bad enough, he could absolutely be the right guy for their careers.