The USA is not like Europe. There are two separate ecosystems here.
DC fast charging
DC fast charging is for enroute charging of 10 to 30 minute sessions. You charge between 10% and 80% here; the car slows down after 80% and it's not worth waiting.
These are blisteringly fast, and restore 5 to 25 miles per MINUTE!
Just enough time to run into McDonalds for pee and quick snack. Not enough time for a sit down meal. Some half-wit put a very fast charger right next to the National Corvette Museum, that placement is kind of dumb. You are charged for leaving the car too long. The charger will tell you how long it will take to 80%.
The two ecosystems are Tesla and CCS. There is also a vestige of CHAdeMo remaining but don't you dare take one of those, that's "hard mode" lol.
If it's a Tesla, that's that. The Supercharger network is very well developed and sufficient for demand, so you are unlikely to be queued up, and unlikely to need the other networks. Most other network terminals do not have the ports to support Tesla (some do) but you are unlikely to find them. There are adapters to dock a Tesla to a CCS station sold by Tesla but they are costly.
The other major system is CCS. The major players are ElectrifyAmerica, EVgo and a few others. You can check chargers in your travel area on https://www.plugshare.com/
The Tesla network is generally superior but for Teslas only this month. Tesla keeps promising to open them up.
AC destination charging
Destination charging is much slower charging intended for hours (e.g. a leisurely meal), all day or overnight. This uses ordinary household AC power at low enough rates that they can go just about everywhere. They restore 15 to 35 miles per hour of charge.
Because of the low cost and ease of putting them anywhere, countless random parties offer these units, and they aren't dominated by major chains. Check Plugshare.com.
Many are free, e.g. at hotels and more progressive cities. Many are free to customers.
Again, two different ecosystems - Tesla and everyone else. Most places have both plugs, and Tesla has a J1772 adapter reasonably priced and provided with every car - make sure you are given one. Don't leave it at the hotel! They both use the same very simple control protocols, so the adapters are nothing more than copper and plastic.
Hotels are usually savvy that you will arrive empty and want to leave full, so they will typically provide 48A gateways for 25-35 miles per hour. The charger is actually on the car, and some cars' chargers are limited to 32A. (Some are lower still, but I don't expect to see them in rental pools).
