Hey, I don't recommend SLovenain skiing at all! Tickets might be more expensive than in Austria and the slopes aren't maintained well. On top of that, the trails are short. Most Slovenians are going out to ski, like Austria, Italy, and France.

If you insist on choosing a Slovenian ski place I recommend Krvavec (he he only 30km of pistes) and next one Kranjska Gora (20km of all together pistes)

Here you can check or some more info, I think this is good for orientation
https://www.bergfex.com/slovenia/top10/

You can Easily go to Austria VIA Korensko Sedlo border. However, IDK about Austrian restrictions about COVID. They are much more strict about it. Maybe you should check first. And ask in Kranjska Gora about the border if the snow conditions are ok. Sometimes that border might be closed due the hard snowing.

If you will need anything else let me know