For stains, the best protection would be a ceramic coating specifically designed for leather such as Gyeon G2 Leather Shield. Below is a post I found on Autogeekonline.net about this product.
If you don't want to go with a coating but still want some protection, you can use something like Optimum Protectant Plus.
And in case you do get a stain on your seats, you want to have cleaners available to clean the stain as soon as possible. Depending on the stain, you can use Optimum ONR or a dedicated leather cleaner. For a really stubborn stain, you can try Optimum PowerClean diluted 10:1.
Last suggestion - over time UV rays from the sun can damage your leather. I would consider getting ceramic tint that blocks most of the UV rays, especially on the side windows because, unless Tesla changed their most recent glass, those windows offer less UV protection from the factory.
From Autogeekonline.net:
I would get a coating and the one I would look at most is gyeon leather shield. Get a gyeon leather cleaner to use before applying and when needed. Maintance cleaning a damp mf towel only. A simple thing to apply and maintain. Give a link to a review and write up by the Guz also. The one thing with any leather coating is to test it before in a inconspicuous space for a week or so. Best to do that or you would be hooked to the look it gets since it's not possible to be polished of like on a paint. So even if eager to use it do that test spot before and let it cure full time. Then you know what you get with whatever coating you chose.
The easy application is a benefit since you don't need to wipe it off. Long lasting and the protection you are after. And as paint coatings they are not bullet proof but for wear and contaminants it's good.
Review - Gyeon Leather Shield (Leather Coating)
GYEON Q2 Leather Shield