You're not going to be able to sign too many high impact free agents with this attitude. I've seen your posts across threads and you're looking at "overpaying" as a roster-wide concept but each free agent is a one-off. You're correct that if you just overpay across the whole roster you'll eventually be mired in mediocrity. But each individual free agent will have their own market. Teams who are making up for lost value at other positions and/or have a specific weakness they need addressed will be willing to overpay for a player in an isolated situation. So if you want to land any of the higher impact free agents you're going to need to step up to the plate at that contract level. The key is to be selective and only do it on a limited basis where it makes sense.
IMO, I'd limit myself to paying top of the market prices for two situations:
1) when the player is worth it, obviously
2) isolated cases where having a higher end (even if not true tier 1) player at a spot has a positive effect on the rest of the roster
I believe Higgins would fall into #2 category there. Is he a true top tier #1 receiver? Probably not. But I believe he's GOOD ENOUGH that he will add a respectable top threat so the #2s can be the #2s and the #3s be the #3s and so on. It will help keep coverages more honest which can help reduce pressure on the OL because defenses can't be as free up front and it make the reads easier for Maye and help his development. Right now we lack any semblance of a #1 WR but even a lower end #1 WR would have a positive pervasive impact on the development of the rest of the offensive unit.
Because of how much teams prioritize the WR unit now, even a player of Higgins' caliber is rare to hit the open market without age or injury concerns. In the rare event they ever do come available, it's usually via trade for significant draft capital. IMO it would be worth it because of how it jump starts the development of the rest of the offense.