Is there a way to sort my favorites by tags?

Nope. There's a script you can use with the TamperMonkey browser extension to sort through your faves on R34, but I don't think there's one you can use with this site. Maybe you could get the R34 script to work with this site of you're savy (TamperMonkey scripts are editable), but don't quote me on that.

I think those scripts also requires a scan through your favorites before you can sort them. Unless the site itself has an api that searches within your favorites like gelbooru or e621, there's no easy way to do it.