This is the sixth Kodansha English volume. It's weird, as volumes 1-5 were omnibus editions, containing 2 of the Japanese volumes each, but the series finished with only 11 volumes in Japan.
So this is the same as the Japanese volume 11.
If I had known there would only be 11 volumes total... water under the bridge.

This is volume 6 of the omnibus series that collects volumes 11 of the original series. Do not combine this with the original Japanese edition of volume 6.

Originally published in Japan in 2021 by Ichijinsha Inc., Tokyo, as Wotaku ni koi wa muzukashii volume 11.

Contents: Chapters 78-86 -- Afterword -- Special Interview: Fujita -- Translation Notes