There are many quirks with creating the virtual interface ap0. You have to follow exactly a sequence, otherwise it won't work. If other applications bind to the wifi port it cannot be set.
create a virtual interface ap0 for the access point
start access point daemon hostapd using interface ap0
start wpa_supplicant for wifi client using interface wlan0
The solution passed to remove the service file in /etc/systemd/system/hostapd.service.
Using cat in this file, because nano wasn't able to open it, I saw that the file was corrupted, so I delete the file and now, I am able to start/stop the service, and everything related.
Thank you to the ones that have tried to help me!
From Reddit, one of the users told me how to solve this problem:
Ah, ok - that's looking better. It does remind me that the tutorial is a bit old and Tor keeps changing configuration options. You'll notice in the log that it's ignoring the TransListenAddress and DNSListenAddress entries. This used to force the whole thing to break but it's been a little odd ...