My observations based on looking at the rosters on the TRC website. I'm quite certain I am wrong on a few of these. I'm also certain everyone will correct me where I am!
Milton-Union loses the least. None of their 15 1st or 2nd team all-league players were seniors. They lose 2 starters on offense (OL and 2nd RB) and 2 on D (OLB and Corner)
Riverside I think loses 3 OL? plus their 2 best receivers. QB and RB both return. On D I believe they return 8 starters. correct me Riverside guys if I'm wrong, but I think if they find guys to catch the ball they will be tough again.
Northridge loses Turpin and Holmes, plus a WR and a bunch of linemen. Henry and Marcus Tyree are tough though. Good duo to build around.
TC loses a bunch. I think they return their QB and 2 OT's on O? (help me out yak, am I forgetting someone?). And the younger kids didn't get reps because they didn't play JV (correct?) probably a rebuild year.
Miami East loses Francis for starters. Also Wittenmyer and Rose, but not too many to overcome. I think Ritchea and Roethe lead their 2022 resurgence.
Covington is a tough one. They lose their best players (Wagoner and Sindelir), but they had to play soooo many young kids. I think they get better and coach gets higher numbers out in 2022.
Lehman loses McFarland, which is a huge loss, but returns O'Leary. I think they build around him. They big question here is obviously coach. This hire could really help or hurt.
Bethel loses Reittinger, Wise and 3 linemen. I am not sure what they need to do to improve, but I don't see them getting better on their current path. Changing their non-league schedule would be my first step.