I don't use Dropbox but you could try using alternatives like Mega or Google Drive?

I heard that removing everything after, and including, the question mark in the link is the fix.

I remember having this issue before when providing refs...For some reason in FA Notes, the ampersands in the link are getting converted to & instead of being kept as raw text. This makes things annoying with providing links that have tokens in them...Which is weird because you can type & in an FA note otherwise.
A link shortener might work if it has only one token and no ampersands, but I think the easiest way to do things with no addition is this:

Try putting a space or newline before the first & in the link, something like this:

blahblah...link?dl=0 &e=2&blah=blah;&bleh=bleh;

Then tell the receiver to copy the link address from the first part so it's not shortened with the ellipses (...), paste that into the address bar,
then copypaste the second part (& and everything past that) to the end of the link.
This should result in a working link.

Looks like the links are getting truncated or are having issues with HTML encoding, probably due to the "&" symbol. Try copy+pasting the links from the reply box in the meantime. (The reply box being the writable section of the note field, below the read-only section above it.)

Dropbox appears to have suffered some manner of outage. The only way I know of is to simply use email.

I just tested in a note-

Normal link which should have the broken bits due to FA changing it (& is replaced with amp in the URL itself)
https://www.dropbox.com/scl/fo/qxnu71fkw0yq0l5fd1x6h/AJPRQpkAPRvv7vig-_A4xeY?rlkey=ot1hcxbh4no9froe7iw5yvrei&dl=0

Same link with &dl=0 removed at the very end should work I think
https://www.dropbox.com/scl/fo/qxnu.....9froe7iw5yvrei

I'm really glad I saw this journal and the replies, because someone just pointed out a link I'd posted wasn't working, and if it weren't for this, I would've had no clue that the issue was the ampersand xP