As stated before suplpatcher is currently not working for Xperia 10 Mark III as diag structure for AOSP 11 has changed from previous releases (you will get error 22 when executing the binary).
However I already patched my dev version and on my first QA test on a freshly flashed device I made some very interesting observation.
[root@Xperia10III defaultuser]# ./suplpatch --disable --aosp 11
______ _____ __ ___ __ __
/ __/ / / / _ \/ / / _ \___ _/ /_____/ / ___ ____
_\ \/ /_/ / ___/ /__ / ___/ _ `/ __/ __/ _ \/ -_) __/
/___/\____/_/ /____/ /_/ \_,_/\__/\__/_//_/\__/_/
SailfishOS Xperia X devices A-GPS SUPL Patcher v0.0.1.8 (git: 2c48d52, build: 08.06.2022 09:11)
2022/06/08 09:16:01 ------------------------------------------------------------------------------------------
2022/06/08 09:16:01 SailfishOS Xperia X devices A-GPS SUPL Patcher v0.0.1.8 (git: 2c48d52, build: 08.06.2022 09:11)
2022/06/08 09:16:01 Command line './suplpatch' launched with the following flags ...
2022/06/08 09:16:01 --aosp=11
2022/06/08 09:16:01 --disable=true
2022/06/08 09:16:01 --enable=false
2022/06/08 09:16:01 --info=false
2022/06/08 09:16:01 --remove=false
2022/06/08 09:16:01 --upload=false
2022/06/08 09:16:01 --version=false
2022/06/08 09:16:01 Executable launched as user 'root@Xperia10III'.
2022/06/08 09:16:01 Secure SUPL mode already deactivated.
2022/06/08 09:16:01 Bye.
On my first run of the fixed patcher binary I was told that secure SUPL was already disabled. That means that an unlocked Xperia 10 Mark III devices can change to the non-secure Google SUPL port without patching the device, i.e. just follow my suplpatcher instructions without running the patcher binary and you are sound.
FYI: I updated my device to latest Android 11 via OTA update and then did the flash dance.