MacBook Air starts to Prohibitory Symbol/“No” Symbol

Hello all,

I have been having an issue with my early 2015 MacBook Air where it starts up to a 🚫 symbol. On this computer, I have macOS 10.15 Catalina and the latest version it can run, macOS 12 Monterey dual booted in two separate APFS volumes. I was going to boot into the Monterey partition to free up some storage space, which is my main partition on this computer. When I did that, a progress bar showed up that was going way slower than it normally would. That is unusual, as Monterey does not display a progress bar when I boot it up normally. Once it gets to the halfway point, the progress bar shows the “🚫” symbol. However, the computer boots into Catalina fine. I tried running First Aid on the startup disk and it still would not boot. What should I do? Does this involve wiping out my Monterey partition? Please Help- greatly appreciated! If you can help in any way, thank you so much!!