Is there a consensus by historians on whether the Mongols could have conquered Europe to the Atlantic?
Yes.
Unlikely.
Why unlikely?
The Mongols conquered powerful, populous and huge empires such as China, the Khwarezmian Shahdom, etc.
Russian principalities, although divided, were also not an easy target to conquer (and Rus was allied with Cumans - a militarily skilled nomadic peoples considered strong regional power at that time). We can't rule out the possibility that the Mongols would have been able to conquer entire Europe.
Europe contained no any equivalents of as powerful empires as China or Khwarezm in the 13th century.
Europe was more fragmented and much less centralized than China or Khwarezm, which on one hand made them unable to mobilize as huge armies at a time, but on the other hand made this territory harder to control after the conquest (there would have been many rebellions in various places).
Perhaps imposing a tribute and / or some sort of subordination was more likely achievable for them, than establishing Mongol administration.
Ruthenian principalities, after all, were also never directly subordinated to Mongol administration, but were only paying tribute (Yoke).
Hungary and Poland were rolled over by Mongol armies, but were not subordinated or forced to pay tribute to them in any way whatsoever. But in case of continued efforts and further military campaigns, that was achievable. Hungary was very devastated already after the first Mongol invasion.
It is also not true, that the Mongols were unskilled in capturing fortified places like forts, strongholds, castles, towns or cities.
In general it is not true that cavalry-based armies are unable to do this. There are examples of cavalry-based armies transporting siege engines with them on horse-drawn vehicles (or constructing siege engines after arriving at a certain place) and then capturing strongholds with their use.
Mongol army is one of such examples. And Teutonic Order also did this in many of their raids carried out by cavalry + support of siege engines.