I am confused. Lopez came back on 14 Mar 2022 and has played 12 games, starting 11, averaging about 23 min per game. In April (5 games) he averaged 18.5 pts, even managing 43.8% from 3. Unless there is something new, I believe he is very much in their rotation as a starter.
With that said, yes, MIL is going to be a tough out for anyone but so isn't PHI, MIA, BKN, and of course Boston. Matching top 3, Giannis-Tatum, Middleton-Brown, Holiday-Smart, we probably only win one of those match up. Our depth is a little better but not really a whole lot better. Horford and Lopez are probably a wash and from there, they have Portis and Hill who are both pretty good bench veterans. MIL is a really good team right now.
We probably match up the worst against teams with size but I really have no idea which of the teams we are likely going to need to beat (BKN. MIL, MIA/PHI) are going to be the toughest for us to beat. It may be in descending order meaning BKN toughest, MIL next toughest, MIA/PHI "easiest".