New iTerm2 Window Here option open two tabs
There is open issue iterm2 opens two window or two tabs when launched from services where possible workarounds are described (also root cause of the problem as well).
From productivity point (if you end in shell anyway) you could consider switching to console based file manager (like vifm, ranger, nnn, Midnight Commander etc). You will get productivity boost from relying on keyboard only. There is also command-line fuzzy-finder fzf which could be handy.