I'm not sure if the entire functionality can really be replicated, but Firefox does have a pretty good add-on selection, maybe you can find one that suits your needs.

Because this is not the first time I've heard about Vivaldi tab management, I looked over a couple videos and it really seems impressive, props to them for doing something really cool in this department. However I know myself, and I'd use maybe half the features that are present, most likely even less. If this is also true for you, I'm almost sure a Firefox add-on could be a suitable replacement:

https://addons.mozilla.org/en-US/firefox/addon/tab-manager-plus-for-firefox/

https://addons.mozilla.org/blog/too-many-open-tabs-extensions-to-the-rescue/

https://addons.mozilla.org/en-US/firefox/addon/sidebery/

At the end of the day you obviously don't need to switch if you don't want to, I would just be really amazed if it turned out the main tab mgmt features from Vivaldi were never added to an add-on.