Start over sourdough starter?
My starter is maybe 9 months old but has gone downhill since 2 months ago when I left it in the fridge for 3 weeks and then refreshed it with water from an unclean bowl. It had already smelled of acetone whenever I took it out of the fridge but always did fine when I refreshed it and smelled fruity when I refreshed enough. After the unclean bowl, it now has a funky smell that reminds of cheez its sometimes or what I think beer might smell like during fermentation. I've already switched to a clean jar but that didn't do anything. I've been trying to feed it every day since then, tried multiple combinations of 1:1:1, 1:2:2, 1:3:3, etc switched to bottled water, but not only does it rise slow, it still has the smells and bit of acetone. Tried apple cider vinegar for a couple days, it rose a lot higher but the cheesy smell returned after I stopped and stopped rising as much. I have baked once with it before and it works but no sourness or flavor unlike before.
I've read many posts but no conclusions so far and wondering if I should just start over. Any advice is appreciated as I've spent a lot of flour trying to return it back to where it was before.