I've been using Anker chargers and USB-C cables exclusively since the USB-C transition half a decade ago. They fold up neatly and deliver more power at a fraction of the size of a standard ThinkPad charger.
Five countries, both 220 and 120 and I haven't had a single issue and they are used daily.
You can do non-OEM and still be fine.
Regarding batteries, non-OEM is pretty much the only way to go if you are beyond the Lenovo warranty period. You can't even get fresh batteries from Lenovo for 8th generation machines anymore.