Persist state (after reboot) for timers

Currently I use timestamps on MQTT to have persistent timers, for my lights and other stuff that need timers, because these will survive a reboot. I would love to use timers instead of this home-brew, but then they would have to persist.

I could imagine 2 different types of persistence: One where you simple continue where you left off and the other using a timestamp to calculate the remainder once hass is restarted.