I totally agree with what you’re saying.
2015 was an absolute masterclass in how to botch a rebuild. The team severely underperformed in 2014, and I along with many others were saying to rebuild then. They didn’t. (Supposedly because of ownership, but who knows). Instead, they upped Homer Bailey, who was an analytics darling but hadn’t been that great with regularity on the field. They held on to all the expiring contracts until the last possible second, and by then injuries, underperformance, and pure rental contracts minimized their returns. Saddled by the Bailey and Votto contracts, and with minimal returns when trading their big named players, that rebuild never had a chance. The only reason the team became competitive later was because of the returns garnered from Strailey and Simon trades.
So those trades made the team marginally competitive in 2019, when the team made one of the worst trades ever in trading their very few prospects to get downward spiraling Puig, an oft injured Alex Wood, the contract that offset Bailey in a washed Matt Kemp, and the surprising WAR leader of that trade, Kyle Farmer.
None of those rebuilds had a strong enough foundation to succeed. I hated the signings of Moose and Castellanos because it was prolonging the time the team was in the middle. But this team, from the pitching to the young batters, has the foundations. It just needs to be supplemented, as you say, with a big bat in the OF. The failings of previous GM’s shouldn’t dictate how the new management operates. Don’t rebuild this team, but do sell off expiring contracts, because this year seems a lost cause.