Your best old post deserves a second run
Most people post something once and never touch it again, even if it did well the first time around. I keep a short list of my strongest performing posts and revisit them later, either as a fresh clip cut a different way or a caption rewritten with a slightly different angle. The core idea already proved itself, so I am not gambling on something untested.
This matters because new followers never saw your older material, and even people who did see it the first time will not remember it later. Treating a good idea as single-use throws away proven material for no real reason at all. The work of finding a strong idea is the hard part, and you already did it once.
Try this today: look back through your posts and find the one that clearly did better than the rest. Cut it a different way, change the opening line, and post it again as if it were new. Track whether it holds up a second time around.