Is it possible to lubricate the wheel bearings and axles of the bicycle? Isn't there a concern that the bearing grease inside will flow out?

It is possible to lubricate wheel bearings and axles.
If a small amount of stock solution or spray is applied, grease will not flow out,
If a large amount is applied, it may flow out depending on the situation.
If you are worried about undiluted solution or spray, please use the grease type.