@Pierre0 I think you have incorrect information. If you are not eligible to receive an RFC number, Airbnb will charge the guests 20% occupancy tax and submit it to the Mexican tax dept. If you do submit an RFC number, guests will be charged something like 3-5%.
At least that is my understanding from the info provided by Airbnb. I have been closed to bookings since March 2020 due to Covid, so I'm not fully up to speed on all this.
But if you own a place in Mexico, and rent it out, it is actually illegal to earn money here without paying taxes on it- you can't "forget about it". And you also have to pay 16% IVA on your earnings. You should consult a Mexican accountant who is familiar with Airbnb/SAT regs.
I would suggest that you apply for temporary residency and stop entering as a tourist.