I was thinking of trying the spool mods that use bearings, but I don't have any bearings.

I don't want to have to buy bearings. 

What I did have was some brad nails.

This design uses 3D printed rollers and some 16ga brad nails as axles. The reels do not move very quickly at all so I wasn't worried about heat or friction. Bearings would move more freely but you do want some resistance in a de-reeler system.

I've been using this design for quite a while and it's been working great. Most filament reels should fit. I've tried 500 gram reels and they work fine. I haven't tried 250 gram. The cardboard reels from Overture, Duramic 3D will work only if you print one of the various guide tubes that are available. I have been using this adapter: https://www.thingiverse.com/thing:5201319 

Maximum reel width is 76.5mm

Printing Instructions: See photos for build orientation.

Should work with any filament. I have used PLA and PETG for mine.

Rollers: 

Best to print them on-end. I did not need a raft or brim but you do need very good bed adhesion.
3 Walls minimum. 20% infill is fine.
In PrusaSlicer I set seam to REAR. The seam tends to be at a slight angle but I think it's better this way, more of a gradual bump. 
Depending on the print settings, filament used, you may need to chase the hole with a 5/64" or 2mm drill bit if the nail doesn't go through. In cura the z seam was very rough and required sanding. In PrusaSlicer the z seam is perfect and requires no post-processing at all.

Roller Frame: 

DO NOT PRINT VERTICALLY. It will look a bit better but it is not strong. It will break in half. Use support under center of arch. Tree support in Cura or Organic supports in PrusaSlicer worked very well with default settings.
You may need to chase the roller shaft holes with a 1/16" or 1.5 to 1.6mm drill bit depending on how accurate your print is. The nails inserted fine for me.
 

Clamp: 

Print on it's side. I printed with 100% infill and it really doesn't take much longer. 

Assembly: Refer to exploded view picture.

Hardware needed:
(Qty 2)  M3 screw, 10mm to 12mm long will work. Cap screw or button head.
(Qty 4)  1.5 inch, 16 gauge Wire Brad Nails. (Shaft is 0.063" dia, Head is 0.095" dia)
I don't think nail gun brads will work.

Push the nail point into end of frame, through a roller and press it in fully.
There is a shelf with half-circle which is meant to press against the nail head for retention.
Add a drop of glue if desired, but the nails press in pretty hard so not really needed.
Place roller frame over stock Creality roller tube. Install clamp on opposite side. Install screws.
Note that there is a built-in gap between clamp and roller frame. You should not try to close the gap fully. A 12mm long screw will take a while to thread in but it does work.

The design was done in OnShape. 

Edit: 11-1-22: Updated the frame and clamp. Increased the amount of plastic around the mounting holes for the clamp. Clamp mounting holes in frame are now through-holes so they don't accidentally fill up with supports. (Yes, I did it once…)

Edit 3-28-23: Frame was updated to Rev A1. Added a radius to the exit side of the screw hole for clamp to make it print better. No functional change.