My vendor security patch level for Redmi Note 9 Pro is 5 June 2022.
/e/OS 1.11-s-20230521 works fine except that the battery drains much faster than with the previous release. This seems to be a known issue and should have been fixed for most devices with 1.12. However, builds for v1.12.3 failed for several devices including miatoll, see https://gitlab.e.foundation/e/backlog/-/issues/7112 . When looking at LineageOS, which is the basis for /e/OS, newer versions are built https://download.lineageos.org/devices/miatoll/builds