https://www.celticsblog.com/2022/4/6/23013290/playoff-seeding-frenzy-boston-celtics-milwaukee-bucks-philadelphia-76ers-miami-heat-tie-breakers[This article assumes that MIA wins either against ATL at home or @ORL. and clinches the 1st seed.)
Boston goes 3-0
    Clinch the 2-seed
    If Celtics and Sixers go 3-0: Celtics 2 seed, Sixers 3, Bucks 4
    If Celtics go 3-0, AND Philly and Milwaukee finish with the same record [ED: as each other]: Celtics 2, Bucks 3, Sixers 4
Boston goes 2-1 with their only loss to Milwaukee
    Bucks win tiebreaker from Celtics
    If Sixers go 3-0 and Bucks go 3-0: Bucks 2, Sixers 3, Celtics 4
    If Sixers go 3-0 and Bucks go 2-1: Sixers 2, Bucks 3, Celtics 4
    If Bucks go 3-0 and Sixers go 2-1: Bucks 2, Celtics 3, Sixers 4
    If all teams go 2-1: Bucks 2, Celtics 3, Sixers 4
    If Bucks go 2-1 and Sixers go 1-2 or worse: Bucks 2, Celtics 3, Sixers 4
    If Sixers go 2-1 and Bucks go 1-2: Celtics 2, Sixers 3, Bucks 4
    If both Bucks and Sixers go 1-2 or worse: Celtics 2 seed
Boston goes 2-1 while beating Milwaukee AND Chicago
    Celtics win tiebreaker from both Sixers and Bucks
    If all three teams go 2-1: Celtics 2, Bucks 3, Sixers 4
    If Sixers go 3-0: Sixers 2, Celtics 3, Bucks 4
    If Sixers go 1-2 AND Bucks win over Detroit OR Cleveland: Celtics 2, Bucks 3, Sixers 4
    If Sixers go 2-1 AND Bucks go 1-2 or worse: Celtics 2, Sixers 3, Bucks 4
Boston goes 2-1 while beating Milwaukee AND Memphis
    Bucks can regain tiebreaker from Celtics in any scenarios from above where the two are tied by beating both Detroit AND Cleveland, by virtue of better record against conference
Boston goes 1-2, with their only win over Memphis OR over Chicago
    Celtics lose tiebreaker to Bucks
    If both Bucks and Sixers finish 2-1 or better, Celtics become the 4-seed
    Bucks hold tiebreaker over Sixers
    If Bucks go 3-0 AND Sixers go 2-1: Bucks 2, Sixers 3, Celtics 4
    If Sixers go 3-0 AND Bucks go 2-1: Sixers 2, Bucks 3, Celtics 4
    If Sixers go 2-1 AND Bucks go 1-2: Sixers 2, Bucks 3, Celtics 4
    If all three go 1-2: Bucks 2, Celtics 3, Sixers 4
Boston goes 1-2, with their only win over Milwaukee
    Celtics win tiebreaker over Bucks
    If both Bucks and Sixers finish 2-1 or better, Celtics become the 4-seed
    Bucks hold tiebreaker over Sixers
    If Bucks go 3-0 AND Sixers go 2-1: Bucks 2, Sixers 3, Celtics 4
    If Sixers go 3-0 AND Bucks go 2-1: Sixers 2, Bucks 3, Celtics 4
    If Sixers go 2-1 AND Bucks go 1-2: Sixers 2, Bucks 3, Celtics 4
    If all three go 1-2: Celtics 2, Bucks 3, Sixers 4
Boston goes 0-3
    Bucks win tiebreaker over Celtics AND Sixers
    If both Bucks and Sixers finish 1-2 or better, Celtics become the 4-seed
    If both Sixers and Celtics go 0-3: Bucks 2, Celtics 3, Sixers 4