Plug-ins are always a personal choice. For me the most essential is fuzzy finder with ctrl-P. With this I can arrive at any file or line in a massive codebase damn near instantly.
I find vim with the right plugins is as capable as any IDE, you can at least have the basics like autocomplete and various syntax highlighters and linters. Personally I think developers who lean heavily on the IDE features of more common tools are using it as a crutch for not knowing the codebase very well or language features.
Part of the journey to vim mastery is the configuration of vim until it fits you like a glove, once you’ve configured it well you rarely need to touch the config files again.
I've been trying to spend more time in vim since last year because I can imagine a world with the benefits you describe, and I want to put in the long-run investment to get there. But at the same time, Vim naturally lacks the feature set of an IDE, and setting up a bunch of plug-ins so that they all work together is somewhat time consuming and brittle.
I've been wondering if I should stick to Jetbrains/VS Code and use Vim as a text manipulation language, and whether I'd still attain that editing fluency you describe.