Usually users can post from any instance to any federated community on any server.

Unless the federation between lemmy.ca and Lemmy.ml is wonky/broken, one of the servers is overloaded, or they’ve explicitly forbidden it, you should be able to post there.

Shouldn’t posts be less likely to flop here though? The communities have less content, so they move slower and people have more time to see a post, making perfect timing less relevant, as opposed to reddit for example.

I agree with the crisis comment though