There is a deleted scene of Kylo Ren from TLJ looking out the command center of a Star Destroyer while some TIEs fly by which could easily slot itself before we go to the planet because the original shot of Mustafar has TIEs and said Star Destroyer. Add some of those Sith whispers as he stares at the stars, and it would be golden. But there are a couple of problems:

We’d need to see his own ship flying down to Mustafar’s surface to understand how he suddenly got there. Fixing Disney Star Wars commissioned a really talented VFX artist who used to be on this forum to do this for a project (Petrovelly, I believe). Their project is now defunct, and they didn’t have the decency to release these materials to the community. So unless somebody can think of some sort of clever transition method, it probably wouldn’t work.
His outfit is technically different. How much? Not by much. He’s just missing his cape, so I guess this could be handwaved away.