This.
There are a million different resellers, some larger and professional, others probably being run from someone’s garage. I use esimdb to filter to the countries I’m after and then select the plan I want. (total GBs or GB/$) It’s all quite simple.
Currently using a JamboSim offering in Sth America and it has been fine. With this method I think I’ve also used eSIMs from Jetpac, Orange FR, Thirr, Always Mobile, FlexiRoam (former 28 degrees card freebie), Voye, EscapeSim and Nomad. I’ve not found a bad one yet: they all do what they’re supposed to do, connecting to local providers and giving me data in foreign countries. YMMV