The USA de facto surrenders to Russia in the Ukraine war and Europe starts to buy gas from Russia again (if the USA can't protect us we have to buy protection somewhere else). Russia use European money to start buying European politicians again. Eventually they'll politically control all of Europe. Maybe not the UK.
China gets East Asia because a retreating USA must be seen with suspect there too.
The USA maybe keeps the Americas, which however are not very happy with them even now (the countries that don't speak English.) Some countries will try to jump ship to Russia and China. More colonial wars to follow.
Overall effect: reduced reach for American companies, products and services. A small side effect: we won't be here to discuss this on HN but on a site of another country/language. Eventually: switch to a different worldwide common language (France experienced that demotion around the 60s/70s - French was the previous lingua franca) and further reduction of reach. Eventually: a poorer USA.
Seen from outside the USA this doesn't look MAGA to me. The opposite of it. Hard to assess the impact on inequality, healthcare, tuition, etc. Maybe the USA will go the way of the European Nordic countries or they'll implode. I won't get into that.