FreeBSD UFS & fsync

Hi all,
I'm running a virtual machine with FreeBSD 12.2, PostgreSQL 12.5 and
UFS as filesystem.
I was experimenting with fsync = off and pgbench, and I see no
particular difference in tps having fsync enabled or disabled.
Now, the same tiny test on a linux box provides a 10x tps, while on
FreeBSD is a 1% increase.
I'm trying to figure out why, and I suspect there is something related
to how UFS handles writes.

Any particular advice about tuning and parameters that can be
affecting the "no difference" with fsync turned off?

% sudo tunefs -p /dev/gpt/DATA
tunefs: POSIX.1e ACLs: (-a) disabled
tunefs: NFSv4 ACLs: (-N) disabled
tunefs: MAC multilabel: (-l) disabled
tunefs: soft updates: (-n) disabled
tunefs: soft update journaling: (-j) disabled
tunefs: gjournal: (-J) disabled
tunefs: trim: (-t) enabled
tunefs: maximum blocks per file in a cylinder group: (-e) 8192
tunefs: average file size: (-f) 16384
tunefs: average number of files in a directory: (-s) 64
tunefs: minimum percentage of free space: (-m) 8%
tunefs: space to hold for metadata blocks: (-k) 6408
tunefs: optimization preference: (-o) time
tunefs: volume label: (-L) DATA