Older Mac, need video sharpening

[Neil the K]

I created using iMovie a video of clips from multiple original sources. By the time it got exported, re imported, and then uploaded to Youtube, it appears blurry and washed out. I have been researching various on line services or software that may help to increase the clarity, but either nothing is helping or the available software will not run on my old computer system. I've even reached out to some video editors, seems they don't want to bother with it or have no ideas either.

Suggestions appreciated.

[davexnet]

Take a look at the NLE's on this site, you may find one that will run on your mac.
For example, KDenlive, Shotcut, DaVinci Resolve, etc
https://www.videohelp.com/software/sections/video-editors-advanced