This is just a rumor but look at what he has done to make Girona very superior this season. Of course, there will be lots of offers for him from top teams so in my opinion it is very likely that he will leave because for a coach getting an offer from a top team is certainly very difficult to refuse.
However, whether or not the current Girona coach leaves next season, I think it will still be difficult for them to repeat what they have done this season. It is not easy to maintain the consistency of a team if they do not have really strong strength.
If Michel really leaves next season, Girona will definitely experience a shock that could result in a decline in their performance. The opportunity to coach a big club doesn't come twice, Michel will definitely consider the offers that come even though Girona management will try to keep him at the club. Apart from that, Michel must first complete his mission in La Liga, managing Girona to collect more points before the season ends. Rumors regarding his future will continue to circulate as several clubs will part ways with their coaches.
Sometimes we have to really ask why clubs tend to make changes when things start working fine for them. They will want to change the coach or do some things. In the case of Michel I think it should be a matter of a better offer and not that of non performance.
Girona is a club I have just respected since this season. Even without having a solid squad depth, yet they did wonders. I wish the team could remain and even get solidifies for the upcoming season.