Paid off it’s easier to sell for sure because there is no lien preventing the buyer from transferring title. When you have a loan, it must be paid off and the lender has to provide a lien release or termination statement.
How much harder it is would be subjective. Some buyers don’t mind it while others don’t want the hassle. I haven’t dealt with Tesla finance on this so if you have a loan through them you may want to contact and find out how long it would take to turn it around.
This is why I like to use local credit unions. Often times they can turn things around much quicker than the big banks.