Level	Success Rate	Cost	Increment
1 → 2	90%	5,000 coins 🪙	+9%
2 → 3	80%	10,000 coins 🪙	+8%
3 → 4	70%	15,000 coins 🪙	+7%
4 → 5	60%	20,000 coins 🪙	+6%
5 → 6	50%	25,000 coins 🪙	+5%
6 → 7	40%	30,000 coins 🪙 + 1 Red Ticket 🎟️	+4%
7 → 8	30%	35,000 coins 🪙 + 1 Red Ticket 🎟️	+3%
8 → 9	15%	40,000 coins 🪙 + 1 Red Ticket 🎟️	+1.5%
9 → 10	5%	45,000 coins 🪙 + 1 Red Ticket 🎟️	+0.5%
10 → 11	1%	50,000 coins 🪙 + 1 Red Ticket 🎟️	+0.1%

Note: When treasure level up fails, you gain +% increment to the base success rate, up to 10 times total.

Credit to Yosh and Jubilent for gathering data about the treasure system, who gathered the information and posted it all on the discord before I was able to add it here.