Just speaking to Columbus facilities:
1/OHSAA seems to desire avoiding use of member facilities - which is understandable even if a suitable facility is available.
2/While the former Crew Stadium at the Ohio State Fairgrounds is the perfect location in terms of parking, support facilities, and location - the fate of the facility is still in limbo. A major showdown between the legal entity set up to own and manage the facility and the Fair Commission over "who's gonna pay for all of this?" is the near future - Columbus overreached in the deal to build the new soccer stadium, the Crew/MSL are not going to cough up the full funds needed for the renovation, and the Fairgrounds oversight board is justifiably not going allow the City to run roughshod over a state-related facility. My completely unlearned opinion is that the Fairgrounds will wind up with the site, which would be the most favorable outcome in terms of potential for holding football playoffs. Grab some popcorn and pull up a chair.
3/OHSAA can no longer afford to use Ohio Stadium, and TOSU, in the age of million-dollar assistant coaches and pay-for-play college athletes, can no longer afford to subsidize the game. The OSHAA playoffs are no longer a recruiting tool - for a Power Elite school within the Power 5, recruiting is national, and is RAPIDLY shifting to player earning potential under NIL and NFL potential.
4/Fortress Obetz - On paper it sounds good, has turf, and seats 12,000 according to Wiki. However, it's in a dumpy (but not dangerous) area of the metro. I've never been there - impressions from anyone with experience attending games would be welcomed.