This bug appears to be affecting older Macbooks with dual graphics. The problem occurs with the integrated graphics (Intel Iris). Gmaps works normally with the discrete graphics (AMD Radeon). I've sent feedback to Apple & Google, already. Lets hope they fix this one.
Settings > Battery > Automatic Graphics Switching unchecked. Gmaps becomes functional on Safari 16.0, but with considerably more heat.
In general on my old '15 Macbook Pro, I use Firefox for Gmaps because of responsiveness and lower heat production (less fan). Safari is my default browser, but it is sadly lacking in performance for Gmaps.
Do the current Apple Silicon Mac's that use Safari get good performance with the use of 3D Gmaps? Any discernible fan?? Probably time for a new computer!!