Same question here.
I'm Swiss, flying LYS-FRA, landing in FRA at 19h25 and then the following day FRA-MEX, departing 13h40.
No issues getting into Germany, I believe (I will have a PCR test).
I have contacted several airport hotels, explaining I was only in transit overnight. They've all said that if the purpose of my travel is personal they won't be able to accomodate me. How do they verify this? Do I need to show some kind of proof? Can the rules be bent?
That transit hotel airside doesn't look appealing to me at all.