There are 2 development teams for Monster Hunter (maybe even more at this point with Stories, et. al.). So the team that just finished RiseBreak is not wholly responsible for MH6. It won’t be a quick turnaround as it should have already been in development since the close of WorldBorne.
We expect to hear something at TGS based on a comment Tsujimoto has made. Then it would likely release by Q2 2024 based on previous release patterns and the MH anniversary being next year.
All speculation, but pretty solid as far as speculation goes.