The pupu platter carousel was extensive
https://www.basketball-reference.com/teams/BOS/2023_transactions.html
Also go back and look at year before Ainge ariived, 2002 
July 9, 2022
Traded Malik Fitts, Juwan Morgan, Aaron Nesmith, Nik Stauskas, Daniel Theis and a 2023 1st round draft pick (Julian Strawther was later selected) to the Indiana Pacers for Malcolm Brogdon. conditional 2023 1st-rd pick was BOS own, Indiana also receives a trade exception
This one caught my eye. The pu pu platter scrubs all were part of the trade that got us Brogdon. That same day, we signed Hauser, Kornet, and Davison. Not a bad day for such a bad GM.
I'm not sure you understand my point of view. I think Brad has been a really good GM so far. He has added real players to the team that fit a vision and can play, mostly through trade which is pretty much what he has to work with given the team's state. The pupu platter trade for Brogdon was masterful. His draft picks have been good swings of the bat, especially from where he has selected, we will yet see if any of those swings connect.
As to the actual discussion at hand, he has done ok at free agency. Signed some useful players, signed some duds, his best signing got injured and never suited up. As to Roy's main grievance, the signing of g-league level talent over proven vets. Brad has taken lots of shots on the Broderick Tomases of the world (I actually like the search for diamonds in the ruff) but he has probably devoted too much roster space to this endeavor. So far he has a good hit with this strategy in Hauser but think he needs to hit another this year to be considered a successful strategy for a contender.
In summary, Brad's free agency strategy is different for a contending team and probably riskier. Mostly the jury is out. So far it hasn't seen a ton of success but he doesn't suck.
That is all fair. Stevens does seem to favor the prospects over the old vets when filling the the last few roster spots. It is a fair debate. What I disagree with is when people extrapolate this and say things like this approach means the owners don't care about winning. That apparently is not what you are suggesting so that is not directed at you.
The one "old vet" that was signed and did work out pretty well is Griffin. There were cries for Cousins, Howard, Whiteside, Favors, probably some others. All of which went on to do a big fat nothing. And we don't know if they even wanted to play in Boston.
This year, so far, we have signed Brissett and Danton plus carried over Champagnie and Kornet. Not sure who this season's old vets are that we could be signing. I see Brissett as a pretty solid FA signing. He is young enough to have some ceiling but also established enough to not be just a prospect. Kornet kind if is what he is. Being durable and reliably mediocre is his claim to fame. He is a useful enough vet big to be the 13th to 15th guy. Is there a better vet out there? Maybe, I don't know.
This year's "prospects" are Banton and Champagnie, and to some extent Walsh. It is unlikely that Champagnie survives the whole season. Kornet may not either. Banton is guaranteed for 2 seasons so has a deal similar to Hauser. We'll see if he works out as well as Hauser. But even if he doesn't, how bad is a 50% hit rate for this kind of signing?