Not all bearings CAN be silent, and not all yoyos are silent either. It’s a combination of the two. I don’t own one, but my understanding is that you’d be hard pressed to ever silence a Protostar, for example.
If silence is a requirement, about the best you can hope for is to buy a replacement bearing that’s known to be on the quiet side (10-ball from One Drop?) and use a little bit of lube (rather than running dry). Beyond that, there’s no magic.
Some yoyos act as a natural amplifier for noise. Many plastics do this. A few metals do, but are almost never as bad. The Phenom, one of my favorites, is a bit noisy though. The caps and shape, it sounds like a hollow tin can, but the play is amazing and I can use the sound to determine if it’s time to bind it back or not. You can use this feature to your advantage.
A little lube can help, but the odds are usually that it’s the yoyo that’s amplifying the noise due to the material and/or shape of the yoyo. Either invest in earplugs or invest in a different yoyo.
If it was me, I’d clean the bearing out in mineral spirits, use the paper slip method to clean it, then clean it again in Acetone and Terrapin X treat it.
I do have bearings that randomly get louder/quieter. If it doesn’t affect play, I just ignore it and keep playing. I have that issue with lots of different bearings, including One Drops, KK’s, Crucial Grooved, and CBC CenterTracs, just to name a few. I can’t say I have that issue with my 2 Trifectas because I cleaned and treated those and send them off, and right now I’m waiting for those plus 6 others I paid for to come back to me. I won’t see those bearings for a while, I have a big box of goodies those will ship with, so I’m looking at maybe 2 weeks or more before these ship. Why? Other stuff that will be gong in that box needs to be paid for as well. Might as well save on the shipping!