Tchou can send a ball and has some magical touch when on it, but was mostly hyped for tackle timing.
I wouldnt even bother looking into why Tchou wasnt given a look, because it's not how Carlo operates.
Ancelotti has always been conservative to the point he absolutely flat out refused to budge on first 11s to not doubt players status in the team and get them on side that way (even Kroos + Bale in 2014/15 if you look back then) unless he is somehow forced to (injuries or otherwise)
Something Zidane inherited from him really.
Carlo repeatedly said in pressers Kroos and Modric play when fit because their legs dont wobble under pressure (even though they wobble out of age lol)
He has basically not introduced anybody new into the lineup since his time here, only replaced Casemiro with another CM and replaced injured Mendy that was otherwise not in doubt with another player that is fast and athletic enough to make a difference
He may have given Ceballos a shout in a lower tier comp and made Asensio get his one-trick-pony shots on target rather than into row Z, but cemented them well into their place in hierarchy fast
And point will probably be moot if he stays - I'd expect Tchou to be starting come August lol