You gotta "settle it on the field", right?
Once you start going down that rabbit hole, people will keep demanding you expand it if they think a worthy team is excluded, such as 2003 USC, 2004 Auburn, 2011 OkSU, 2014 Baylor/TCU, 2023 FSU, etc.
I say if you don't want them to take a mile, you'd better not give them that first inch.
Smokey, this isn't 'Nam, this is bowling, there are rules.
Just make the caveat that the +1 only happens with 2 undefeated teams, post-bowls.
A +1 pits undefeated Auburn vs undefeated USC in 2004.
The rest of those jokers lost and can pound sand.
'23 FSU is funny, because they were omitted from the playoff because of their QB situation and showings thereafter, but they're pitching a fit and blaming their own conference.
You could let FSU have their +1 if you want, as they were undefeated, but it'd be a public flogging. The line would be 20+ points, no matter who it was against.