I believe I gave up on supporting RHEL awhile back as I had issues, but they may have been similar issues to what I was experiencing with Fedora until very recently.

If I were to guess what the issue was it would be SELinux would not allow me to setup a custom systemd process on the system level. If you want to install Kinto then you will need set that. (/etc/selinux/config) Make sure to set it as permissive.

Beyond that the xkeysnail_service.sh file is executed by setup.py and would need entries added for whatever the distro and dename variables are on RHEL. Should be pretty easy to add support at this point I'd think and Kinto just got updated to v1.2 yesterday - so it has a full on GUI and system tray for some DEs now.