it depends on the mod i think , you can run iso mods , or even things like load the project m mod via the sd-card method ,the homebrew launcher and it apps and ports like sonic mania also working fine
but ican’t say the same fo riivolution stuff for the dolphin core , i know that the standalone version can load this mods via its own folder but thats not the case dolphin core cuz its out of date (tried it with a tetra’s trackers translation ) …
but you maybe have luck with an fully modded nand that can use riivolution , cuz you can use a modded nand/firmware with the dolphin core … i didnt’messed with riivolution on mine but i have my old custom wii nand running in retroarch via dolphin