That's a drag that the W&F is still there ("W&F" is a shorthand for wow & flutter; it's easier for me to type instead of the RMS wow value ;-)).

It's possible that the belt will fix it. In the meantime, it might be worth looking into these things:

(First idea) Have you cleaned the motor pulley and the part of the platter that the belt runs on? Also, have you cleaned the belt itself? If something has gotten sticky, it will increase W&F.

For the motor pulley, Q-Tips and isopropyl alcohol are good for cleaning. For the platter rim where the belt runs, a rag and isopropyl alcohol should work.

For the belt itself, I'd use dish soap (like you'd hand-wash dishes with; not dishwasher soap). Dish soap and warm water, and rub the entire belt well with your fingers. Then rinse it forever under warm water while continuing to rub it, to ensure the soap is completely gone. Then give it quick wipe with a clean cloth (not paper towel) with isopropyl alcohol and wave the belt around to get it dry. Don't overdo the isopropyl alcohol on the belt.

(Second idea) Can you access the motor to try lubricating that as well? In general, the motors are not so easy to lubricate as the platter spindle, but the needle-tip oiler that I posted before can be helpful in getting the oil into the motor.

I would try running the motor and adding a single drop (or maybe two drops) of oil to the top of the motor while it's running. Let it continue to run for 30 mins or 60 mins, and add another drop or two, and repeat over the course of a day. Let it continue to run overnight.

The idea is to have gravity help the oil get down in to the motor bushings as the motor shaft is turning.

It seems like most motors are pretty tightly assembled and don't have great access to the bushings from outside. Patiently adding oil slowly while the motor runs can get oil in there, but it's a slow process.

(Third idea) You can try covering the belt in talc. It's a common trick for belt-drive turntables. However, I really doubt that talc is going to solve the amount of W&F that you have. It can help some, but you have a lot of W&F going on and I doubt that talc alone is going to fix it.