Intellisense is notoriously bad at parsing templates (which you can’t really blame it), honestly the best thing I’ve found is to find disable intellisense errors. The compiler is the authority on errors anyway.
As far as I know, at some point Intellisense started to “understand” UE specific things. Right now I’m using it and it works with everything except that new bug with iterators templates. I really hope it will be fixed in the next releases.