Ability to stick any tab on the side, like Brave Leo

I really wish for a feature to stick any tab on the side, such as Brave Leo or Opera GX (with WhatsApp etc.) has it. This feature would enable users to simultaneously use the sticked tab, while not having to switch from their current open tab. This feature would work like a containerized tab, so it is its own instance, instead of mirroring a currently open tab. Therefore, it has no access to the context of the current open tab, like Leo would have. This does not make sense in my opinion and would “just” open security holes.

I have added a screenshot to clarify my request.