@Vesti check out this video of a guy repairing a Vivosun fan with a similar problem. To remove the bearings you’ll need a puller that most people won’t have, but you could bring the motor to an auto or bicycle shop and see if they can help, that’s the folks who usually have a bunch of bearing drifts and pullers around, but they’re also quite cheap at Harbor Freight or wherever. In the video he just removes the dust seals on the bearings and repacks them, which is honestly what I’d try first. Crack the fan and remove the motor, pull the dust seals and try to swab out whatever dirty grease is in there with rubbing alcohol or mineral spirits and some Q-tips, let it dry in a warm place for a day or two, then repack the bearings with a little squeeze tube of some high speed bearing grease from the hardware or auto store and pop the seals back on. I’ve done this a million times with sealed bearings on bicycles and it works great, frequently they’re just dry inside because the major difference between cheap and expensive bearings, besides tolerances, is the quality and amount of grease fill they get inside. Cheap ones have cheap grease and bad fill, nice ones have space age grease and full fill, with better seals. In this case the cheap bearings will probably help make it easier to pop the dust seals and repack:
I’m a big fan of Super Lube products, they make dozens of different things, their grease and oils are very popular in bike shops as more reasonably priced and bulk packed alternative to bicycle-specific lubes. They even make a ton of food grade lubricants for kitchens and factories that are pretty useful around the house.
https://www.harborfreight.com/85-gram-super-lube-grease-cartridge-93744.html
https://www.super-lube.com/multi-purpose-synthetic-grease-with-syncolon-ptfe
You can get all the bearings, lube, pullers etc through McMaster-Carr, that’s the easiest route though probably not as cheap as shopping around.
That off grid stuff is cool af