After posting on the forum above, I tried with my friends to see if we could actually play tag matches.
We were not able to match up yet. We were able to team up, and all we had to do was wait for the tag-team matching, but the timer in the upper left corner did not appear, and we got a communication error.
Although the result was disappointing, we were able to meet many friends who wanted to play tag matches. I understand that there is no ETA, but I hope that these results will be of some use and that tag matches will be resumed soon.
Thank you for your continued support!
In the Japanese version of Splatoon it’s called Tag Match, but I don’t know what it’s called in other versions. Sorry.
It just refers to the match that appears in pink at the top when you enter the lobby.