It is very likely that the main spindle bearing is either defective or needs lubrication.

On many turntables the turntable will lift off and then the spindle can be pulled up and out, and then you can put some oil in the opening and replace the spindle. It may take some force to pull it out since there may be some oxidation on the metal.

It only takes a few drops of oil. Originally there was grease in there, but it has quite possibly dried out and hardened, and some oil will soften it and get it working OK again.

Use 40W motor oil.

If the bearing is bad, the turntable is junk.