Don't worry buddy, we will all miss this too. Despite the dumb Idol Premise, it lived up to be the spiritual successor to Index Nichijou, which also ended too early just when we finally get Othinus in it. You're not the only one sad that this ended, but we can cherish the fun meme-ories we've had with this manga. Nothing of value is lost at all because it definitely did something the main series and spin-off didn't: Just have some good damn fun.
Peace, and signing off.
P.S. May we receive another godsend 4koma from our AI overlord Kamachi.exe in the coming years, this time with Magic Side Characters. I want more Necessarius shenanigans in Index!