Correct, SyncTERM is not a VT emulator... however the terminfo entry does have a full ACS set that curses should use appropriately, so NetHack is fully playable. I have no idea what watching NetHack on public servers does or is though... If I do add this is will likely be quite far out (a year or two).
Output speed emulation paces bulk APC and DCS payloads
This is intentional. RIP and ZModem aren't so much carve-outs as things that were too hard to pace when pacing was added. It's likely they will be paced in a future release.
Unable to initialize the Wren main menu
Ah yes, you only need files there if you want to override the compiled-in ones... and compatibility can be a real issue as you've found. ;)
Status Display Type 2 doesn't work correctly
Hrm, all I can think of is making sure you don't have overriding scripts in ~/.local/share/syncterm/scripts
Allow use of scrollback after disconnect