In many cases rEFInd can help with multibooting on the same drive (or different drives too, I guess). As with everything to do getting computers to boot, it may or may not work, depending on hardware, firmware, OSes, the number of pigeons in Australia, etc.
If you want to give it a try, on Fedora download the RPM from The rEFInd Boot Manager: Getting rEFInd. If you have GNOME Software or KDE Discover, you should just be able to double click on the .rpm and click install, not sure if dnfdragora or COSMIC Store support this. Otherwise something like sudo dnf install Downloads/refind-0.14.2-1.x86_64.rpm should work. I think it’s supposed to setup everything just by installing the package, but if you don’t see refind when you reboot, you can try running refind-install from Fedora.
If you see refind, when booting up, there will hopefully be a bunch of options to boot from. Look out for ones with vmlinuz in the label - this will allow you to boot the linux kernel directly, bypassing the nightmare that is grub. rEFInd has a tendency to show more options than necessary, so you may have to try a bunch of them to see what works.
Operating systems have a tendency to replace refind with grub or other things when installing, or sometimes even updating. In this case, just reinstall refind, which you can do from pretty much any operating system, or run the refind-mkdefault script on an OS that has refind installed. And if you ever end up stuck in a grub menu, you can press c to get to a grub shell, and then enter exit which will hopefully return you to refind.
Good luck to fellow multibooters. You’ll need it :).