Modify templates in plugins

Hy, I need to change css assets in cookiespolicy plugins without loosing changes in next update. How can I do? It's necessary to fork?

Unless there is something someday similar to inherited themes I guess you'll have to fork.
I had to keep one plugin properly translated but I admit I didn't look further.

There's no need to fork, just override the CSS in your theme. You just use a more specific CSS attribute to ensure it gets overridden.

I suggest you create a new theme and use theme inheritance though.

But what about a twig/template definition? Any way to use inheritance for that? Trying to modify the feed plugin template (to not have the graphic "banner")

Yes, you just need to provide your own version of the twig template in your theme. However, you do need to ensure the path is the same, but as the feed.atom.twig and feed.rss.twig files in in the templates/ folder of the plugin, you just need to copy and edit them directly in your theme/templates/ folder.

Thanks... will give it a shot :-)