For me SMB with v6.11.3 is performing about the same as v6.11.0, there is a small though measurable slowdown, especially with large files, my guess is that they are caused by the Samba update from v4.7.0 to v4.7.2 which includes some CVEs:
samba: version 4.17.2 (CVE-2021-20251 CVE-2022-3437 CVE-2022-3592)
But note that this update was done on v6.11.2, so v6.11.3 should be very similar to v6.11.2
P.S. tests are done from one Unraid server to another, both with the same release, I tried before doing Windows to Unraid tests but they were not repeatable after some time, i.e., a test done 6 months later could produce very different results, likely because of the Windows updates installed in the meantime.
P.P.S. only did tests with mitigations=off for now, though AFAIK no new mitigations in the kernel since v6.11.0.