This is only my personal opinion I have been waiting to publish a few packages and did not publish them in version 13 because I knew things would change considerably in 14. Version 13 and earlier use angular JS for packages in the back office whereas going forward packages will use web components in version 14 and onwards. Alongside the use of web components and Umbraco have released a component library called Umbraco UUI and to maintain the stars consistently within the back office if you use these components within your app they will suit and Umbraco perfectly so no need to use any other CSS framework. https://uui.umbraco.com/?path=/docs/uui-action-bar--docs

Excellent step to use new languages but targeting v 13, 10, 8.. still important because of clients using them.

AFAIK you can use UUI in V13

I already tested the library but now seems receiving new updates. Maybe it is a good choice for other Umbraco plugin using

Lit

.