Honestly, I would try another class. I've grown attached to almost every new character I've made. Each class has a different playstyle (some have multiple), and stamina and magicka characters play very differently from each other. If cost is an issue, you definitely don't need all gold gear for alts—just gold weapons is fine.

Failing that, you can try another different/off-meta build on your character. Some people like to learn how to solo world bosses and dungeons, but that would probably take a different build from what you use. Have you done Maelstrom Arena?

If what you want is quests, DLC sounds like the best option for you. The Reach is REALLY good for quests IMO, but you need Western Skyrim as well to fully finish the questline (there's an epilogue questline for when you finish both). Southern & Northern Elsweyr work the same way. Murkmire is another very popular DLC questline that is totally standalone. Vvardenfell is part of a three-zone story with Clockwork City and Summerset, so you could finish that story up, too.

And of course—there's always housing! Lots of houses can be purchased for gold, and making the perfect home/dueling arena/temple/crafting hub for your character can be very addicting once you start—and give you something to farm for lol.

If you like collecting things, the Antiquities system you get with Western Skyrim has LOTS to collect.