Welcome!
There are lots of posts on ceramic coatings, PPF, paint protection, etc on TMC. Just try searching using these terms.
What are your goals for your paint protection? If you want to protect your Tesla's paint but don't want to spend a lot of money, you can hand wash it once a week and apply a spray-on sealant like Turtle Wax Seal and Shine or Turtle Wax Flex Spray Wax once every 3 months. A ceramic coating, which is a higher level of protection, is like a semi-permanent wax. You can either have one professionally applied or apply one yourself. You will save money if you do it yourself, but make sure to do your research. Consumer ceramic coatings can be relatively easy to put on, but they are not very forgiving if you make a mistake. Paint protection film is the most expensive form of protection. It has self-healing properties. Minor scratches and swirls just magically disappear in the heat of the sun.
Probably the most popular form of protection for a Model 3 is to put PPF on the most vulnerable parts of the car (front bumper, hood, rocker panels, etc) and then apply a ceramic coating on the entire car. If you want ultimate protection, you can put PPF on the entire car and then put a ceramic coating on top of the PPF. But that can run over $6,000 .
So it really depends on your budget and your needs. You can either go for the $8 bottle of Turtle Wax Seal and Shine or you can spend over $6,000 on PPF and a ceramic coating.
Personally, I would not use a car cover. No matter how careful you are with it, it will scratch your clear coat. I would only use a car cover if I was storing the car for a long period of time, or if I had a full car PPF. If you have a full car PPF, then you don't have to be as concerned about inducing scratches with the cover.
Hope that helps,
joebruin77