Currently now, most paper cups are with Pe lined inside. which making it recycling difficult and often end up in landfills. Also for the PLA lined paper cups it's just commercial commercial. That's why people care more about the home compostable paper cups .

Yes, most  paper hot cups and cold drinking paper cups are contained polyethylene plastic lining (5-10% of cup weight) and may have trace amounts of processing chemicals, though regulated as food-safe.

Standard paper cups are difficult to recycle due to the plastic lining that makes them hard to process in standard recycling facilities. The pla lined and aquesous coating paper cups are commercial compostable and biodegradable, while the PPC-P paper cups is home compostable and biodegradable.

Compostable biodegradable paper cups:  about 6 months. Plastic-lined cups: 20+ years as the plastic layer prevents proper decomposition.

Yes, you are right, often the single wall paper hot cups are for hot drinking. So if you need quality one, then the double wall coffee cups and ripple paper cups are good choice for you.

Nowdays,most customized disposable cups are with polyethylene plastic lining , NOT wax due to melting issue and more safe to use.

Yes, paper cups are more eco-friendly to the environment than plastic cups.

Reusable cups (ceramic, glass, stainless steel), compostable PLA-lined cups, bamboo fiber paper cups, aqueous coating paper cups  OR ppc-p paper cups.