I hear this phrase all the time in real life but I’m actually not sure if I’ve ever encountered it when reading. It’s a colloquial phrase that basically means “let’s call it a day” or “meh, good enough” or similar vibes. You kinda say it when you’re doing something and the outcome is a bit テキトー but you can’t be arsed putting more effort into it.
I hear it often as まあいっか、これでいいってことにしよ
I tried to look for examples in the wild but I couldn’t find any relevant one, but this article does use that phrase.