Trying to edit the EFI of a usb boot drive I made on mac (opencore)

This is probably gonna sound dumb, but I wanted to update to big sur on a new bigger hard drive I bought, so I followed the opencore guide but I got stuck in a loop when I try to boot. Anyway, I can't boot into my old mac drive (luckily I have a backup of all the data) but I can still boot into windows (which is where I am typing from). I want to edit the USB booter I made, but I don't know how to access it on windows (or get to the EFI so I can change the kexts and config.plist and whatnot) since its formatted as macOS Extended (HFS+) with a GUID partition map

is this a possible task?