Managing the tax is going to be an issue moving forward, no doubt, but this tends to only be a problem when you have signed players to more than they are worth. Or more specifically, you are not getting your money's worth out of max or near max contracts.
In the case of the Celtics, there is only one contract, Kemba, that is in this category. I am fine paying Tatum, Brown, Smart, Thompson and even Fournier (all the rest are low cost rookie type deals). Kemba is a bit out of whack but I am not sure really how much.
He is averaging 19 pts on 15.5 shots per game and pitching in 5 assts. as a shoot first type PG. His 3p% has climbed up to 36% (he was 38% last season) in what is a "down" year for him due to injury. Plus he brings leadership and a history of hitting big shots.
In trying to find some "comps" for Walker, CJ McCollum is at about 23 pts/5 assts/39% 3p and making $31M in 2021/22. Yes, I would rather have CJ at $31M than Kemba at $36 but if CJ is fair at $31M, would Kemba be fair at $20M or $25M? Brogdon is at about $22M which seems like a really good deal but in the range. Lowry is at $31M. Holiday will be $30M next season.
My point is yes, we have one "bad" contract but even that one bad one should not cripple the team. The way things have worked out with signing Kemba and Tatum coming due and put us in a tough spot but I think in a few years, we will be back well within the norms of the top market teams.