Are you 100% sure that the motor is fully disengaged from both cables?
It is starting to look like bad news.
I still think there's got to be a piece in there somewhere. Either that or the cable is dicked up.
If the motor is disengaged that lower guide should move pretty freely.
If it's jammed up then either the motor gear is not fully disengaged or there's still something in there, or the cable is damaged somehow

 

Where the yellow arrow is pointing in the pic, concerns me. You need to investigate that and see if there's a little piece broken away from the lower guide, or if it's just the grease making it look bad. Look up and down that slot beneath there, see if there's a piece in there, and look under the middle there, just past the arrow. I usually run a wire tie under it to see if anything's caught.

Next, grab where the red arrow is pointing and wiggle. It should only move slightly. If it moves much, that's your problem.

 

Ya, it doesn't even move a millimeter, as if it's welded in place. I'll try to lower the motor even more maybe that's still catching? But when I press the button on the front controls and the motor runs it's very quiet now compared to before when it made the grinding sound. I'm gonna try to see if there's anything else that could cause the cables to be stuck before I choose my last step, either;
1) just putting things back in place as-is and just forgetting the fact that a sunroof even exists in the truck (since I rarely used it and haven't for the past year since it's been acting up)
2) buy a full track replacement piece, remove the headliner, and install brand new track and cable kit. But I'm having trouble finding the correct part(s) for this full replacement...

Any other insight or options are greatly appreciated!

 

that is a Mopar sunroof you linked. I'm not aware of any rebuild kit for this model. They do have one for the old ones, 14 and down.
it's either the arms, or the whole track. Only option we have at the moment

 

Yes - I grabbed the wrong link in the 50 tabs I got open 🤦🏻‍♂️. Is it possible to purchase the whole track? I checked a few auto part sites online and they don't seem to have it. I'm only finding options on eBay for buying a used, in-tact, setup which also includes the glass?

 

Yes, many dealers have the new tracks in stock. I don't know why they show no part number online but they are readily available. I just diagnosed a 2016 yesterday at a Ford dealership and they have the track in stock for that one.
I don't think you're going to find one for any $600 though.

FL3Z-16502C22-E

I believe that is the correct part number, but definitely check with the dealer first. The online manual says it's only fits 17 to 20, but I'm pretty sure that's not correct. There's a cut off in there somewhere where they changed how the deflector installed and I thought it was around 18.

 

Ok - good to know. What does that part typically run? $1800 or so?

 

here lately the parts departments have been pricing them up around $1,900 to 2,000. They have gone up a lot in the last year or so. Two years ago they were only about 12 or 1300.
online you might still find them for that. Definitely call a dealership with your VIN number and get the part number

But they're definitely available. I put in 3 last month, 2 2016's and a 2017, all the same track #.

 

I took the day off yesterday and got back at it around noon today...
- Removed the entire headliner out of the truck. (Didn't remove the seats, just turned and turned and took it out through the front passenger door)
- At this point I was able to see the "dicked up cable" as some had warned may be my problem... 😵‍💫
- Lowered the big sunroof "track" and was able to get some needle nose pliers in there to attempt to detangle the mess of a cable that was jutting out of the top of the track. I was able to untwist one loop but it's still quite curved and won't feed back in to the track.
- Here's some pics of what I found ... this was all right at the point where the sunroof glass motor interacts with the left & right lower guide cables

I believe my choices at this point are (a) to semi-fix it at no more cost to me, (b) fix it all the way for another $2k, or (c) have the dealership fix it for $3k-$4k
A - Snip the cable off to allow me to move the lower guides forward enough to put the new replacement lift arm in on the driver side, then reattach the glass and button everything up. In this scenario, I'll have a working sunroof shade but an inoperable sunroof glass.
B - Buy the replacement part (i.e. the big sunroof track piece) for ~$2k to have a fully operational sunroof shade and glass. I'm worried about the airbags going off in the upper areas around the bolts I'd need to access to remove the old track and reinstall the new one... is that a risk?
C - let the dealer do it all, for $3k-$4k

I'm leaning towards A, but B is tempting if it's reasonable to think I could find a used part for $500 - $700 (and the air bags concern isn't an issue)?

 

Okay, that's a bad one. I was afraid this is where we were heading.
Yep, there's no alternative here other than to replace the track. It's possible you can snip the cable and get the guide to the closed position and disable it. No, there's no worry about the airbags.
Sorry for the bad news there that you found
If you have the headliner out, you're most of the way there already. Personally I'd go ahead and do a track