They don’t have voting rights in presidential elections, they only pay a portion of federal taxes compared to people who live in the 50 states and DC. Here is a link for Puerto Rico, you can go down to political status within the US and read that section and the one after. https://en.wikipedia.org/wiki/Politics_of_Puerto_Rico

Another link about PR taxation. https://en.wikipedia.org/wiki/Taxation_in_Puerto_Rico

Puerto Rico has always voted down becoming a state (although if I remember correctly when they voted during Clinton the vote was very close, I think back then they blamed voter turn out for it not passing). I assume people mostly don’t want to be a state, because their taxes would go up, but also I think some just have pride of their country Puerto Rico, and although they are Americans, they are Puerto Rican too. In fact, it is worth noting that many Presidents have supported statehood both democrat and republican.

This link lists all the territories with links at the bottom for information on each territory. https://en.wikipedia.org/wiki/Territories_of_the_United_States

Unfortunately they tend to governed like banana republics. Policy leans to supporting industries that have paid off government officials.

The Marshall Islands became a hub for clothing manufacture thanks to its nearly nonexistent worker rights, poverty wages, and tax incentives for the manufacturers. Arguably the only people who benefit are the deal-makers.

Puerto Rico saddled itself with a huge amount of debt then proceeded to privatize a lot of infrastructure such as the electrical grid and the biggest highways. As a predictable result those resources have not seen adequate levels of maintenance and investment and revenue is hijacked by the ‘investors’.