I've switched most of my work that used to use moment over to Luxon[0] now. It's still written by the same authors, but fixes a lot of the drawbacks[1].
Also, if you find you only really need one or maybe two date time utilities, date-fns [1] is an alternative that that takes an even more modular approach for tinier imports.
I'm using React Widgets[0] and I prefer moment over Globalize (been through so much pain with this). Maybe it's time to either write a localizer for Luxor or find a new date time picker
Depending on your specific needs [0], a lot of date localization can be done (painfully, but possibly) directly with Browser Intl [1] calls instead of a library.
[0] Current user's current locale is easy. If for some reason you need to show some other locale than what the browser is using you'll likely still need Moment or Globalize.
Also, if you find you only really need one or maybe two date time utilities, date-fns [1] is an alternative that that takes an even more modular approach for tinier imports.
[1] https://date-fns.org/