There are rpm packages of imagemagick on their site but required dependencies are missing. so, the dependencies are in EPEL repo but which EPEL repo should I use for fedora 35? 7/8/9?
EPEL is not meant to be used in Fedora. Did you consider using Toolbx and create a CentOS 8 toolbox? Download page of ImageMagick mentions Redhat/CentOS 8.3 so I think a CentOS Stream 8 container will do it.
I see Remi providing ImageMagick7 for Fedora for quite a while now, so that’s worth trying:
I don’t see a bug about updating the official Fedora package to ImageMagick7 yet, but I expect the maintainers are aware of the new version and will update when the right time comes. ImageMagick6 (now called legacy) is still maintained, so the Fedora packages continue to receive updates.