Review on SYUAB 9Pcs NE555 DC 12V Delay Timer Relay Switch Module: Adjustable 0-10 Second Converter Timer for Efficient Time Control by Mike Littlejohn

This device does exactly what I need. You can set the delay time. After turning on. The device delays for the set time and then switches on the relay. The relay remains energized until power is removed. Unfortunately, when I installed it in my project, it crashed within minutes. My guess is that the 555 IC has failed. Another reviewer elsewhere pointed out that the issue could be EMI due to a single power supply. But I have no idea why mine failed. I burned 6 pieces.