"We were pretty heavily invested in our team in the past few years."
A great statement to dig into and examine. The question I think that this statement should invoke is "can an NFL team truly balance, in a salary cap era, fully stocking a current roster and simultaneously rebuild?"
Leaving aside the uncontrollable variables: injuries, retirements, suspensions, etc that cause roster holes in both the moment and across multiple seasons, can a team realistically, and repeatedly, constantly "reload" vice having to decide to reset?
If the answer is "yes" then wouldn't the following also have to be true - the team MUST hit on (skill position (incl T, LB and CB) starter in rounds 1-3 and at least playing/contributing backup for all other rounds) not just some, but the majority (say 70-80%) of all draft picks in at least every other year regardless of where they select; have all cap clearing measures (such as unscheduled renegotiations (a la Gilmore)), RFA offers, restructures, cuts, option years, etc) go the teams' rather than player's way; and all free agent targets must sign for (and actually be signed as targeted) what the team initially offers?
I don't think all of those is realistic (nor has ever been achieved by any other team in a "perfect" scenario say across a typical five year span where such "rebuild or reload" decision would naturally arise under the current cap and draft system).
In the cap era, most NFL teams are likely to have one or two of those "must be true" corollaries occur with an already in place core; however subsequent years quickly cause those corollaries to exert their force on any roster precipitating a skew toward either rebuild or reload - not both simultaneously.
Reality is more a choice constantly being made right after each season concludes - spend to the cap/trade for with existing stars/players/free agents "in the moment" looking to prop up a roster for the "now" with hope of draft success allowing you to recoup some of that if you do hit on some picks as not just starters but impact/star level immediately
OR
Clear up or gather resources (cap, picks, both) maximizing flexibility you sacrificed for talent "now" to reshape a majority of one or two phases of the team (offense/defense - I do contend you can reshape an entire special teams roster in a single year).
I don't think that, unless the QB and other cap crushing positions such as WR, play at well under market value, a team can balance both reload and rebuild and instead must choose which plan they will execute.