I've been through both. Modded a Wii and applied the settings noted in the video. Ultimately I was hooking it up to a 4k TV on composite cables.
Those same settings can get applied to the modded virtual Wii on the modded Wii U - but connected by HDMI.
The Wii U didn't have a great catalogue (and much of it was also released on the Switch) but it does have some unique ones, like the only re-releases of the Wind Waker and Twilight Princess. Plus there is a huge arsenal of virtual console games from NES to DS.
The Wii cost me $50, the Wii U was $100. The extra $50 was well worth it.