Maplibre (https://maplibre.org/) offers a beautiful open source solution. There are affordable open source solutions for OSM base maps too (https://github.com/protomaps/basemaps), where you can host the whole thing as a single static file.

No one should be paying Google per API key :)

True, but they were still resource constrained, which might be why they ended up with a model with lower resource requirements.

Those mega corporations have intentionally misused the term “algorithm” which implies an unbiased method of ranking or sorting. What they are actually using is more like a human curated list of items to promote that supports their self serving goals.