Exactly, as a solo developer I can't imagine making a cross-platform app in 3 different languages and perhaps developing a landing page for the app in a 4th com

Exactly, as a solo developer I can't imagine making a cross-platform app in 3 different languages and perhaps developing a landing page for the app in a 4th completely different stack. I'd much rather learn 1 stack well, write the app once, and spend time _optimizing_ it rather then _reimplementing_ it.