The UEK is more dedicated to following long-term-release kernels. Oracle's re-wrap is known as the "Red Hat Compatible Kernel."

v7-rhck-3.10.0-1160.92.1.0.1

v7-uek-5.4.17-2136.320.7.1

v8-rhck-4.18.0-477.13.1

v8-uek-5.15.0-102.110.5

v9-rhck-5.14.0-284.11.1

v9-uek-5.15.0-102.110.5.1

Kernel version 3.10 has always been stock rhel7's version, but the UEK has jumped through v4 to v5.

Red Hat made a big deal about io_uring availability in v9, but I am guessing that it is available in v8's UEK.

I will say that the Oracle database group's support for v9 is very poor at this point; for some reason, they are holding to v8, and releasing few products for the newer platform.