So I've done some testing, and I got the Mario Kart Wii problem fixed, I just used an old save. However I still get the slow channels and internet problem.
I tried your method along with every other method on gbatemp, wiibrew and dolphin forums but nothing seems to help. I have tried formatting the wii system memory, tried reinstalling the cios but i still get error code 101246 and channels are really slow to load. Also on mario kart wii it says...
when i try connect to the internet on the good ol' wii, i get error code 101246. this wii is softmodded and has riiconnect24 so i don't know why it says this?
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