open-source alternative to Roll20

I want to create an open-source alternative to Roll20 on the DH2 system with features from BetterRole20. What do you think? It will be a browser-based version. The main thing I would like to achieve is responsiveness and user-friendliness of the interface. This idea was born mainly when we encountered the problem that Roll 20 was loading poorly in Russia and that images were periodically loading poorly.