Ok I think I've now resolved the issue for my setup and it has removed all intermittent glitches and lags (however small). In short, the fix for me was to reduce the Stall detection wait time from 128ms down to 64ms in m2lagfix for my setup.
The reason i can think of why i'd need to do this is because is because i migrated my setup to PC with faster CPUs (but who really knows)
I found the original m2lagfix sourcecode within SailorSats respository
https://github.com/SailorSat/m2lagfix and recompile it in a version of VB6 professional i found in archive.org.
In the m2lagfix source code - I just replaced line 224 "If GetTickCount - STALL_Tick >=
128 Then" with "If GetTickCount - STALL_Tick >=
64 Then"
I've put my code changes in a fork next the original m2lagfix (named _stall64ms) and dropped a compiled exe (m2lagfix_stall64ms.exe) here in my github:
https://github.com/dekkit/m2lagfix_stall64ms/Please note on windows 10 triggers an alert in defender (i'm not sure if there is a way around it - but have shared the source code in case someone can compile or wants to port this to a newer language without this issue)
Sharing in case this helps anyone else experiencing or scratching their heads trying to resolve the random glitches in there setup.