Appreciate your response!
I experimented as per the instruction. I tested all 3 versions of 5.4 on Linux(plus 5.4 Win version on Win PC), and ran 5.3.1 via Wine on Linux.
Curiously this time Win version is the one having issues.... Still using SDOJ as reference (I picked SDOJ because I spent quite a bit more time on SDOJ than Futrari at the arcade I once went to offering CV1000 boards
Win 5.3.1 build on Linux via Wine appears to run the same as on Windows 10 (no sound jitter during cinematic slowdowns).
Both Linux 5.4 builds appear to have same behaviours compared to each other; the aforementioned "erroneously all-time present bullet slowdown" did not appear on 5.4 Linux builds. however the "abnormal audio jitters during cinematic slowdowns" reported previously still persists.
Words really can't express my gratitude towards you, MAME team and all the other emulator devs.

