Hey Brian,
I have attempted to create delay circuits using the 555 timers before and it isn't very straightforward nor accurate. I have an example below using the TLC555 timer. If a solution such as the one below is desired I can certainly help with the implementation. I believe a better option would be to use a dedicated chip such as the TPS3818 or something similar.
I searched for an automotive grade supervisor that may fit however the team that supports these devices would be better equipped to find the right device. Below is a link for what I have found
. https://www.ti.com/power-management/supervisor-reset-ic/overview.html?keyMatch=TPS
Let me know if I can be of further assistance,
Best Regards,
Chris Featherstone
