Try -X. Vim will try to connect to an X server on startup. A slow connection can make that noticeable. That flag will turn off that feature, at the cost of some of the X integration not working.

is this opening a remote file, or a local file?

Local files. I'm able to replicate if I open up a Clojure project for example, but only the first time I open it. The second time it's instant. I think I've seen it happening with a Dockerfile as well as ruby files. But at the moment, I'm concentrating on Clojure projects. So as suggested by @U09LZR36F I've used the :profile function and then asked vim to open a project.clj file. This is the only thing that seems to have consumed 90 seconds:

FUNCTION  <SNR>42_scrape_path()
    Defined: ~/.vim/bundle/vim-salve/plugin/salve.vim:166
Called 1 time
Total time:  97.017427
 Self time:   0.022392

count  total (s)   self (s)
    1              0.000002   let cd = exists('*haslocaldir') && haslocaldir() ? 'lcd' : 'cd'
    1              0.000002   let cwd = getcwd()
    1              0.000000   try
    1              0.000008     execute cd fnameescape(b:salve.root)
    1  97.017363   0.022328     let path = matchstr(system(b:salve.classpath_cmd), "[^\n]*\\ze\n*$")
    1              0.000006     if v:shell_error
    1              0.000004       return []
                                endif
                                return map(s:split(path), 's:absolute(v:val, b:salve.root)')
    1              0.000001   finally
    1              0.000029     execute cd fnameescape(cwd)
    1              0.000002   endtry

Yep. I've never used salve because I find it too slow.

I assume your problem is having a snapshot dependency, and it's being checked against maven for the latest version.

that sounds plausible. I'm not even sure why I'm using salve, will investigate. Hopefully it is the only problem and I should assume other slowness was because I had a project.clj in the folder

Sounds like you've tracked your issue down, but FWIW I sometimes get issues like this with neovim if I've recently opened remote files (eg on NFS mounts). In those cases, I delete the recent file history with rm ~/.local/share/nvim/shada/main.shada