So, from what I've been testing, the latest stable version for the IR working is v15.3.0 ,released on 1 Jul 2020 (I can't send you the link, but you can find easly in the Github page of TWiLightMenu). It's said that the v18.5.0 correct this feature, but it couldn't work for me (even restarting...
So, I have aproblem that I can't fix alone. I'm trying to connect my Pokewalker on a Soul Silver ROM (in Twilightmenu++ v19.1.1, using nds-bootstrap Ver. Release v0.38.0 in my Old 3DS) using a japanese cartridge of Heart Gold as a vessel, but I couldn't. The connection doesn't happen. I tested...
I may try the new ram site, and download more RAM to my Switch. Not sure if ddr3 is the right ram
for it tho. Edit- no it uses floppy Ram, just like @AncientBoi