Seiffen in Orbe Mountains

Perhaps you mean the Ore Mountains, the Erzgebirge. With an early start, you can get there in just over 2 hours with a train from Dresden-Plauen to Freiberg (Sachsen), then a bus to Seiffen.
https://www.rve.de/

You can get to Seiffen by rail/bus from Dresden; be sure to check the schedules carefully as service is not very frequent. It is easier to access by car. Also, I believe there are tour companies in Dresden which offer day trips from Dresden to Seiffen. Perhaps check Get Your Guide, as well as the direct website of any company that offers such a tour.

The Erzgebirge (Ore Mountain) area is very beautiful!

We were there 3 years ago. Rent a car. I would not want to rely on a bus in this rural remote area. Give yourself time and flexibility Additionally, hours of shops can be inconsistent. They may close early or just time their hours with the occasional tour bus. A car will get you there relatively quickly.

There is so much to see and driving to Dresden you will pass the nutcracker museum in another nearby town. It was closed when we were there- maybe due to the day and off season. It looked cool.

Bring an extra suitcase or better yet, have the shops send items to you. (Depending on tariff situation- we were there when $800 de minimus rule was in place). Know before you go.

There are many beautiful shops loaded with fabulous hand crafted finds. It is impeccable quality and craftsmanship.

We stayed at the centrally located Buntes Haus. Parking is available. You will walk all over town. There are hills. The roads in and out are mountain roads- curves, elevation and two lane.

You might consider Annaberg-Buchholz too. With more time to Oberwiesenthal, but that would be more for hiking and not shopping.

With more time to Oberwiesenthal, but that would be more for hiking ...

... and steam train riding ;).

We had an auto and did it two summers ago out of Dresden. A nice day but if you have the time to spare.