If you're purely looking at the integrity of the 2022 season (from a competitive standpoint), then every game that would effect seeding has to be completed. Otherwise there's going to be an asterisk. Which, under the circumstances, may be acceptable to some.
Also, I highly doubt Buffalo is inclined to forfeit an opportunity for the #1 seed, which will make a huge difference (playing @BUF as opposed to @KAN or @CIN). A 14-3 record guarantees them the #1 seed. Also, I commented on this in another thread but I'm sure Buffalo doesn't want to honor their teammate by taking an L for the night. The team will resume playing football, and whenever that is, they will be playing for Hamlin. No better way to honor him from a football standpoint than winning out and presenting a hopefully recovering Hamlin with a Super Bowl ring.
Cincinnati too, still has a shot at the #1 seed with a 13-4 record, or the #2 seed (if KC finishes 14-3). If Buffalo forfeits the game then they can still finish 14-3. If the game is instead discounted by the NFL then they are almost guaranteed the #3 seed. If Cincinnati gets a forfeit win, or a discounted game, then it denies Baltimore an opportunity for the division title.
I know it seems cold, looking at the various decisions, and consequences, but the reality is these are all considerations and a decision has to be made. Whatever it is, it'll probably to be met with disapproval from some corner(s), because there's no perfect solution.