It is not easy to replace moment.js since many libraries like react-dates rely on momentjs. Hope they have plan to replace it.
It would be nice to see more flexible dependencies in such libs for example like material-ui pickers [0] which let’s you bring your own date/time lib.
[0] https://material-ui-pickers.dev/getting-started/installation
You either ship without any date support at all or you pick a library and go. Very little comes close to Moment for i18n and timezone support, so lots of libraries go with that.
The Temporal proposal to replace Date can't happen fast enough.