ftp.postgresql.org/pub/repos/yum/11/redhat/rhel-8-x86_64 :
postgis31_11-3.1.1-4.rhel8.x86_64.rpm
postgis31_11-client-3.1.1-4.rhel8.x86_64.rpm
postgis31_11-docs-3.1.1-4.rhel8.x86_64.rpm
postgis31_11-gui-3.1.1-4.rhel8.x86_64.rpm
postgis31_11-utils-3.1.1-4.rhel8.x86_64.rpm