People will remember but they wont submit. The US got countries to submit to them becuase of the economic sanctions made possible by cornering the energy trade. I dont think we'll see that again given renewables becoming the meta
In yiur example, cuba will remember china's help, but china will have to keep being nice to keep that loyalty, which means conprimising with cuba rather that forcing it like the US could do
China delivers a second donation of 5,000 photovoltaic systems to Cuba: https://www.youtube.com/watch?v=qrvjyZ76Z5w
Panels cost nothing, the balance of system costs and labor will be borne by the recipient. People will remember for 25 years.