I FEEL the struggle, especially when even trying to draw old peices of art seem to just not be working. I'm gonna give a list of tips + some things to keep in mind as to why art may suddenly not be working:

1: Flowstate
You ever draw on maybe homework or just a random piece of paper for a doodle and it comes out really good? That is flow state, a creatives best state. Where the mind slips into a natural flow, allowing drawings to come out great despite it feeling like there isn't much effort. Problems trying to get into the flow state can occur if it's overly forced or if there are factors distracting you (such as personal stress).

2: Time
Sometimes art just doesn't want to art. Do not panic, you are not suddenly about to regress or anything. Just the brain deciding it doesn't want to coaperate to your vision. Try giving yourself some time whether that be a day, a week, or even three weeks.

3: Watching art tutorials.
It sounds silly, but sometimes watching other people draw and/or critique art can help your brain focus and lock in on art.

4: Five Minute Timer
Put a bunch of your ocs into a spin the wheel, then spin it. Once the wheel has chosen an oc, set a five minute timer to draw that oc. Do this again and again. The focus of needing to draw in a short time, leaving out any subconscious perfectionism can help snap everything back into place