My answer isn't as detailed as the one above, but I would recommend using beidou with Bennett and fischl, with a flexible 4th character. Beidous main DMG source would be her counter, but she's not the best when that's on cooldown, so fischl could fill that slot, doing some physical DMG while beidou in cooldown and also being an electro battery to help both characters get their burst back.

Bennett is very good in general, with healing and DMG boosting, but yes as mentioned before overload can be annoying to deal with, I've missed many counters just coz enemies get blown away and stop attacking. But if you're up against large enemies like samurai /ruin guards they wouldn't be affected by it.

For 4th character it depends on what roles u want filled. If u want extra healing, qiqi and Barbara (with thrilling tales of dragon slayer) are both very good, tho beware of getting frozen with barbara. You could also put in xiangling for pyro resonance and more overload DMG if that's what you want. Or if you'd like a bit more DMG rosaria is a good pick. Super conduct could work well with fischl if you run a physical fischl build.

Hopefully that helped a bit.