I also dev on an ultra wide. I suggest doing nearly all your play testing in window mode with various 16:9 and 16:10 resolutions. Besides that being the way most of your players will experience it, it's also a good habit to make sure UI elements are properly position and scaled.
Other player-guiding things that come to mind are just visual cues. Simpliest would just be different colored parts of the floor that act as a path.
Here's an idea that just popped into my head, since your level is a castle in disrepair, if you player is on a large platform, have a short wall surrounding the entire platform. On the place where you want the player to jump off, have the wall broken up. Players will naturally be drawn there. You can zoom out as they approach to subtly hint to them that they're on the right track.
Another idea, you have large torches that act as checkpoints. When the player lights one of these torches, have a line of smaller torches on a wall light up in the direction you want them to walk. The player doesn't have to see the whole path ignite, just enough to get them walking the right direction, then they can follow the torches.
Or maybe have a room with rats or cockroaches that run away when they see your light, leading you to the exit.
I'd suggest looking up some videos on metroidvania design and how to guide players.