Hi! Just a quick suggestion, you said that you get only about 70% of your revenue on Steam, so why not decrease the price in Itch to about 90% so that people will prefer to buy from itch, cuz of the low price than steam. And if they buy from Itch, you'll get 90% of the revenue on itch, 70% on steam, but people will prefer Itch.
Just an example calculation of mine :
$7 From Steam BTP will get $4.9 (70%)
$6 From Itch BTP will get $6 (100%)