I suggest that expensive flat corded moulded soft polymer notched belts are worth the money.
Do not use lubricants or anything sticky.
If you get your belts from an industrial engineering supplier they cost very little.
This is the Gates bible.
Download the pdf and keep it handy (25MB).
A V drive belt is a generic part with a V angle in degrees, a top width, an outer diameter and an inner diameter.
There is no such thing as a genuine part (these are cheap rubbish designed to suit the supplier, not you).
Any belt with a central cord is rubbish (these usually have a fabric wrapping or no visible cording).
Cheap belts eat pulleys, bearings and tensioner assemblies. These all cost a lot more to replace than the price of a high quality belt.
Machines are built to a market price not a utopian ideal. The best service and pulley, bearing and gearbox life comes from fitting high quality belts from new and relegating the originals to the 'spares' box.