Hmm, I haven't heard of any open source projects re-implementing Google's client library, and I imagine it would be difficult to keep parity with a closed-source project.
Most open source efforts have consolidated around MapLibre GL https://maplibre.org which is a maintained fork of Mapbox GL before their switch to a source-available license.
Most open source efforts have consolidated around MapLibre GL https://maplibre.org which is a maintained fork of Mapbox GL before their switch to a source-available license.