how to apply patch 34672698 with non-agreeing versions of grid and db homes

On an R&D server we have:

• Red Hat Enterprise Linux Server 7.6 (Maipo)
• Grid infrastructure 19.26
• several Oracle homes in 12c and one in 19.19 running under this grid infrastructure
• We have one db in 19.19 home

That 19.19 db has performance issues e.g. resulting in timeouts although there is no unusual load on the db.

Found in alert log:

ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM], [Check traces and OS configuration], [Check Oracle document and MOS notes], []

I see a reduced priority only for vktm of this db45588 45588 19 ora_vktm_<db>

For pmon I have "/user.slice":$ cat /proc/45441/cgroup | grep cpu11:cpuset:/6:cpuacct,cpu:/user.slice$