There is a help page that says to contact support it indexing takes more than 24 hours. More than three weeks now, so a message has been sent to support. Hopefully we will learn something from that.
The game became indexed today: https://itch.io/search?q=pushle
Hooray...
Patience seems required for new developers, and we did not get any reply to our message to support yet. (So we do not know if there were any special reasons for why this process took several weeks.