Not mocking cobol devs but yall are severely underpaid for keeping fintech alive

That's crazy. If you have the skills don't under value yourself. Don't be afraid to walk away from an offer. Never tell a potential employer your current salary and never give them a number if they ask in interviews. Ask what their range is as a response and if that matches your number, proceed. Then negotiate for the max of their range. If you get to that point, they already want you, so you have the upper hand in negotiation.