Yes, it’s used to make oilcloth but as far as I know, you’d have to leave the garment to dry somewhere with ventilation for a week or more. However I’ve not done it so if that isn’t the case please correct me.

A cheap solution is to wax some thrift store or old trousers. Beeswax and paraffin, there are different ratios to experiment with, and premade bars you can buy. You rub some on and heat with a hair dryer or clothes iron (with parchment paper so the iron doesn’t get wax on it). It’ll darken the cloth. The more you put on the more waterproof and wind-resistant it’ll get. For bike pants you could focus on the front of the upper thigh and coat the rest less, leaving some breathability on the back.

Modern bikes being less maintainable is largely on the extreme low-end like Walmart bikes, or extreme high end carbon-fiber nonsense designed for rich weekend warriors.

Best if you find a shop that deals in second-hand bikes and get a cheap one. A bike that has been maintained by such a shop is likely to continue being maintainable. Plus you may not know what kind of bike you like til you ride it for a while so don’t spend too much for your first one.