For dealing with multiple files at once, I would recommend using buffers and ideally a fuzzy finder, such as fzf. I would almost advise removing nerdtree while

For dealing with multiple files at once, I would recommend using buffers and ideally a fuzzy finder, such as fzf. I would almost advise removing nerdtree while you get used to using buffers, as it probably shouldn't be used for a lot of tasks that it's tempting to use it for. I also use a buffer explorer plugin and LSP servers too (go to definitions, find references, etc.), but buffers and fzf alone can be very powerful.