This. Exactly this.
Equally bad [IMO] is/was that Lynn is old and fat, which makes it unlikely for him to fight off age-related regression and injury long enough to make sense to re-sign him. So, if 2021 was the year that they decided to go "All-In," and push in all their chips, it was dumb to back the Lynn acquisition with Cease as the #5, and no bench depth to get through injuries. Especially, given that LAD and SDP look to be flat-out more talented than the SOX.
In other words, they punted on the longer-term by giving up 6 years of Dunning, while NOT doing enough this offseason to increase their margin for error in THIS season. That is, if 2021 is, in their view, "their year."