normally you'd press f3 again and a little message box would pop up that tells you what's hogging resources, but from that screenshot i
can notice that the audio memory usage is abnormally high (i've gone and tested a few levels and i haven't managed to get it above 50mb on my end, while you have 200mb). however, that doesn't seem to actually be causing much notable slowdown judging from the frame average, so personally i'm not sure. maybe you can give some of your system specifications and someone on the dev team can take a look? not sure if they'll come across this thread so you can try asking on the discord server as well.