What MPEG2 decoder to use? Other questions.

[cdw2000]

I'm having a lot of trouble getting stutter-free playback on SageTV and was wondering what others are using for their MPEG2 decoder.

Here's my setup:
AMD Ryzen 5 3400G CPU/GPU on AsRock micro-ATX board;
BIOS and all drivers - latest versions;
16 GB 2660 DDR4 memory;
Wired LAN connection to my gigabit router;
SageTV version 9 x64 - latest;
Windows 10 Home edition x64 - fresh install (not upgrade);
HD HomeRun Prime with Cable Card;
OpenDCT - latest version - default setup;
Currently using LAV Video filter set for DXVA (native);
Using AC3 Filter for audio because LAV Audio is way too low volume (any tricks for this?)

I tried to install FFDshow, but they don't show up as available in SageTV as an option - any tricks for this?

Any other filters I should try? (Even payed-for filters?)

Any tricks for OpenDCT? The OpenDCT thread is 136 pages - hard to work out what works and what is still relevant with newer OpenDCT releases.

Video stutters for both recorded and live video. Playing recorded video through other players (like VLC) results in smooth playback- no stuttering.

Also getting weird effect when using fast-forward (jump ahead 10 seconds or 30 seconds) to jump through commercials - The first time the button is pressed I get the SageTV donut for about 2 seconds before video jumps ahead. then immediate subsequent presses are near normal.

Any and all help is welcome.