So, Google Chrome started disabling extensions that didn’t upgrade to Manifest v3, including ViolentMonkey.
A temporary workaround that will still work for a while:
https://reddit.com/r/chrome/comments/1lx26ur/for_those_who_want_to_enable_legacy_extensions
Medium term I think we are saying goodbye to ViolentMonkey for Chrome and only the proprietary TamperMonkey is left. I also saw ScriptCat mentioned GitHub - scriptscat/scriptcat: ScriptCat, a browser extension that can execute userscript; 脚本猫，一个可以执行用户脚本的浏览器扩展 but for now I know that in its current state better-osm-org will not work with it.
But you can always switch to Firefox 