choosing the right patch installer for OS
NB 9.1
Oracle Linux 8 kernel 5.4.17-2136.302.7.2.el8uek.x86_64
Which one of these I should use?
eebinstaller_4040970_14_linuxS_x86
eebinstaller_4040970_14_linuxR_x86_2_6_32
eebinstaller_4040970_14_linuxR_x86
eebinstaller_4040970_14_linuxS_x86_4_4_73
I would say none, they look to be X86 (32bit) installers, you are on a 64bit system.
Since they are EEB, I guess you got them from Veritas Support, in that case support should be able to tell you what EBB to use.
But in general :
S Binaries are in general for SUSE.
R Binaries are in general for Red Hat (Oracle Linux is binary compatible version of Red Hat)
Veritas NetBackup™ Emergency Engineering Binary Guide
Also see : https://www.veritas.com/content/support/en_US/doc/81225970-146133007-0/v149894384-146133007