I have a couple pretty simple things I made to spool and de-spool. Just random [censored] I found around the garage...
The first image is the spool holder. Bent metal, a long nut and a spring. The spring is to put tension on the spool so that it does not spin freely. The nut on the end allows me to tighten or loosen as I need to. To hold it I either spring clamp it to something, or put my foot on it. nice when you are sitting in the living room watching fishing stuff on YouTube and relining your reels.
The second image, even a simpler concept... takes the line off with help of a drill.. that one is pretty self explanatory. I put the drill on high and the line is off the real in seconds.