I'm sort of in the middle. I use Firefox container tabs, but only in the context of a few properties (Meta, Amazon), via browser extensions. I don't manually start new container tabs myself. I just rely on the extensions to open new container tabs when I hit those specific sites.

I wish there was an extension (or, much much better yet, something built-in) that would let me create "container groups" where I could list domain names or URL patterns, and always have them open in an isolated container group.