It could go both ways but i don't think BB is making this a strategy. As mentioned many times Pats are in very good cap position this yr but they are by far #1 in effective cap space next year. So i don't think BB will think about the carryover or artificial concepts like “playoff contender“ “superbowl contender“. As always it should be about making the most of situation, opportunities. If this ends up being spending most of the cap or having a bulk left is secondary. As i see it he goes by a value perspective (all aspects included like comp picks formula etc) not too worried about (but very aware of) cap perspective.
From opportunities standpoint this will be the best market he will ever see. Like you mentioned this will be buyers market, almost garage sale after top FAs are grabbed. So it makes sense to make the most of this opportunity.
The big Q is how will players/managers play this situation. GMs would love to sign players on long term deals in this market but many managers will push for shorter or even 1y deals to wait for better market coming.
One reason teams are willing to unload big chunks of cap to 2023 and after is bc they have some insider informations/estimations re how much the cap will grow after new tv deals and the expectation for 2023 is significantly. In this situation pushing cap forward is both necessity and opportunity, always a bit of a gamble but obviously one most feel ok about. GMs that prided themselves in cap discipline to the point they did not even use prorated signing bonuses are now doing it. So GMs will easily do it as long as owners will be signing the extra checks - bc pushing cap forward costs a lot of real $..