Did you forget who our MC is lolThe real question is how did he find the time to go on a date with only one girlfriend.
The man destroyed the fourth wall and massaged Nozawa-sensei with Momiji so she wouldn't be too worn down from all the girlfriends she has to draw in every new chapter haha
Plus he turned into a super Buddha pervert god thing in that one chapter and extended his legs to have a twenty something plus lap pillow for all of his girlfriends at once somehow.
Finding the time to have a one on one date must be easy to him even while we're amazed at the crazy shit he's probably doing to make it happen lmfao
At this point, the god who gave him a hundred soul mates is probably gonna be mindblown at the end when he sees Rentarou pull it off flawlessly and end up being invited into the pantheon by the other gods lol