I actually did a project doing clustering like that around 2018 using react native, we quickly realized we had to drop down to native for the maps. It was a huge pain in the ass because of the vastly different implementations of google/apple maps and dealing with bridging between native and react parts of the code.

Your project would have solved about 2-3 months of work and ongoing maintenance of 2 devs we had back then. The project is not around anymore but I will keep it in mind if I ever do something similar again.