No problem at all using SafeSky with rented aircraft.
If you have a Premium subscription, you can configure and store multiple aircraft profiles, which makes things much easier when flying different rentals.
There’s no specific rule about deleting an aircraft after your hire period. The important part is simply to make sure you’re using the correct aircraft profile for each flight.
As mentioned earlier, always double-check before takeoff that the selected aircraft matches the one you’re flying. This is important to avoid issues like double echo or incorrect identification.
That’s really the main thing to keep in mind, otherwise, you’re good to go.