The creator still produces a lot of content on their Twitter - and a 2nd season of the anime is slated for July of this year.
More seasons, yes! I assume there's enough material for at least a few more before they reach the 'conclusion' that was Ch.223. The first season ended around the end of Volume 5, I think, which is about 67-69, I think. Of course, they didn't exactly replicate every chapter, but they did put in scenes and interactions from the bulk of them. Anyway, I suspect the next season will go as far as Volume 10, if it covers as much as the last did, which puts it in the middle of the 'magic school' arc, right after the first trip to the past, where Zain encounters Sade, and Viktor meets and converses with his namesake, if only briefly (sure, they probably met before, but he probably couldn't really hold a conversation very well then). Also Sharon awakening, suddenly. Sounds like a decent enough place to stop, to be honest, with anticipation of more.
So... yeah, probably averaging 65-80 chapters a season, with that in mind. V5 ends at Ch.68, V10 ends at Ch.141, and the end of the main story is Ch.223, which may or may not be the end of a V15, but it more-or-less lines up (could be V16). They could slow it down, too, so they cover less chapters per season as it goes, since they start being more plot-heavy as things go forward, and squeeze in a season 4 for the finale, a few years from now (I assume).