I don't really get the logic behind "Holy gate" after boss battles. By testing it out repeatedly I noticed that if MC is virgin they will appear after each boss room cleared, but it's kinda random.
It doesn't depend on evil points gained by items. I thought it's affected by the damage taken, but it's also not true.
If you're unlucky you might not get any portal in the run which makes later areas 4 and 5 pretty hard. And good luck if you've taken Merchant Scenes route - after Scene 3 (Footjob) you'll get an "Oestrus after entering any room" effect. That can royally fuck up your run going forward.
So, my recommendation for spawning "Holy gates": Keep MC virgin, enter Boss room, kill it.
If Holy Gate is not spawned near normal exit - Return to Main Menu (don't press Restart Round!).
Killing the boss and exiting into the menu won't cause the game to save automatically, so when you resume the game you'll have to kill boss again. If you're on Virgin Run - Holy room will eventually spawn.
There are 4 "holy" tier upgrades in that area. Don't use "re-roll upgrade portal" near the upgrade though. In holy rooms this re-roll is bugged and can erase an unpicked item.
There's one upgrade which DISABLE oestrus state completely and one which scales your HP and Attack power in each new area (not room). So these 2 are a huge help, but removing oestrus effect allow you to take other Items which cause oestrus state, which is a good synergy.
At the current state doing Virgin run AND collecting 4 holy items (Hymen Bargain, removing Oestrus state, 'Explosive' clothes when enemies knock you down and Holy Cross after one virgin run completed) makes this an easier to play route now.
I'd recommend to get at least Oestrus removal artifact at the first area and then do Merchant Scene route line... If you're lucky to find him 5 times.
By the way, heavy sword weapon seems to be more powerful and faster right from the start. Seems like they implemented attack interruption frames, so you can dash out mid-combo. So just dash and move more with it.
