Yes, the Pope converting is the most likely way a solution will come. There are around 120 Cardinal electors. If the conservative Prelates are smart, at least a majority (it could be even 20 to 30 on the first ballot, later coming up to 50 to 60) will coalesce around the most conservative/Tradition-leaning candidate. A solution could come like that also.
Fr. Kevin Cusick
https://twitter.com/MCITLFrAphorism/status/986280515232821248 a Rorate Caeli contributor, said he was told Cardinal Burke is now a leading Papabile/candidate most likely to be elected when the next conclave comes.
Pope Michael is hardly a solution. A conclave without the Roman clergy will always lead to a similar result regrettably. Cardinals are an ecclesiastical dignity, just like Archbishops. But you had Roman clergy with St. Peter and St. Paul in Rome (like St. Clement and St. Linus) right from Apostolic times.
Then there are about 5100 Bishops in the universal Church. Trying to assemble all of them (or even a majority of them) at a general Council is very unlikely. I doubt the solution will come like that. Then, there are the jurisdiction issues. I doubt any Bishop will ever agree the last 5/6 Popes were never Popes in the first place, as they would radically undermine their own episcopal authority if they did.
Maybe, they may pass judgment, or make the declaration of nullity against the current Pope in office, but that's it. More likely, the Cardinals will unite to elect the best possible candidate as Pope. Anyway, God is still in control. If in the next 10-15 years, God willing, a solution comes, we can plan how we will re-evangelize the world after that in the decades to come. Setting things right in the Church is only the first stage. Combatting aggressive secularism and all that is wrong in the world will have to take place anyway after that.
Ven. Mary of Agreda says Christ has reserved the triumph over all heresies for His Blessed Mother, and it will be She Who in a special way will extend His reign over the Mohammedans near the end times. Also, the symbol of the moon under Her feet in Revelation is another indication from Sacred Scripture, like "She will crush your head" from Gen 3:15, that Mother Mary will play a special role in defeating this heresy of Islam and all other heresies. Let us pray for the conversion of all non-Christians to Christ and the Church.