This is a very well known speedrun skip in this game. It's basically in every category in one form or the other. Still good to see people in the community re-discovering speedrun skips on their own
In my first playthrough, I entered city of tears by the right. After beating mantis lords, I went into deepnest, take the tram and find the city from kingdom's edge. If I remember correctly I buyed three nail upgrades at once.