Maybe with a Icinga repo subscription you cold get updates as it looks like RHEL is still in “extended Life Cycle Support” until 30 Jun 2028 according to Red Hat Enterprise Linux | endoflife.date.
RHEL 7 is EOL is out of support. Thus Icinga doesnt support it anymore. You could upgrade to something newer like RHEL 8 oder RHEL 9 - but then you would need either a Subscription (Developer or regular), or need to build the packages by yourself. Of course you could also switch to a distro like Debian or Ubuntu and get the newer versions in the icinga stack free of charge.