JUNO's 100's of $M, not $B. DUNE's the multi-$B one, which is in the US, and being a large project in the US, is behind schedule and over budget (full disclosure: I work on that one). It's also not just China working on JUNO, but much of the rest of the world too. Except for the US, which won't fund participation in projects in China anymore.
But my main point: science works in spite of the repressive regimes in charge there (and now here). Some talking head can say wonderful things, but scientists have to actually prove that it works to other scientists. Xi can make a billion people study his speeches, and Trump can spout out a torrent of inanity that gets to scroll on Fox News chirons all day. While big chunks of the world just suck this up and grin, scientific claims get real scrutiny. JUNO's the Real Deal, it's a well done project that will teach us things, and fairly quickly.