I have not had to work on the slide, yet. A couple of 29.3 owners have posted comments about the bent roller plate. On ours it is the plate to the rear of the rear axle which is under the furnace/refer wardrobe area. Mine has bent so bad the screws have partially pulled out.
You can see the rollers when the slide is out by cramming your face to the floor and lifting the rubber sweep under the front edge of the slide. The rollers are mounted facing up against the plates on the slide, would not expect debris to get there very easily. Can probably tell if any are damaged though.
There are two or three access plates under the sofa that allow access to some guide pins. As I recall, you can see outside with the plates removed. May be some issue there that is obstructing movement.
The short wall on the slide between the sofa and driver's seat was binding on the coach floor as my slide was closing or opening for about 6" each way. Made quite a loud squeal/binding sound. Replaced this wall with one with more gap at floor when replacing the sofa with dual recliners. Solved that problem. Before I replaced the wall I would spray WD40 on the floor where it was binding, worked for a week or so then had to repeat spray.
You can check your gear tracks for metal shavings or deformation when the slide is open.
When possible, be plugged in or generator running when operating slide.
Lube the motors and mounts frequently.
Some troubleshooting info:
Lippert Components have a lot of videos that may help and their customer service is good:
https://www.lci1.com/