I recalled the bimetal being on the top in ABB

Now checked - it is on the top in ABB, on the bottom in Moeller (Eaton), Merlin Gerin (Schneider, Chinese clones like the one in your link)

So it confirms it is one of the terminals being a convenient location to fix the bimetal with just a bonus of covering at least one of the terminals , no apparently no difference expected in upper vs lower connection terminal reliability (as both variants were in production)...

Tightening the connections at the breaker did it. Hasn’t tripped since. The breaker stays cool even with the dryer running.