Smart switches with latching relays?

So, at work our department is moving buildings, and I’m in a project where we smartify the existing building.

There’s one problem we haven’t found an easy solution for yet: Some lights are controlled by latching relays in a sub panel somewhere in the building, and momentary switches.

Is there an easy way to get this to work without tearing apart the subpanel (because we’d have to get an electrician for that, and that factors into project costs)?

Two solutions I’m not particularly fond of are: Turn the switches off after a second from within home assistant (which I don’t like because software can be weird), or ditch the latching relays entirely, and use smart relays in the ceiling (which I don’t like because then we’d have to get an electrician and also smart relays).

Is there some obvious solution, or are we just caught between a rock and a hard place?

Replace the relays with these:

Wire them to the existing switches and lights. The switch inputs can work with momentary push buttons.

If I understand your setup. I think you want to install a ‘smart switch’ in the wall to replace a ‘dumb’ momentary button. The issue is that the smart switch need to send a pulse square wave out the wires that go back to the sub panel when the switch is pressed. I seem to remember some of the Shelly devices may have this type function, but it has been a while since I worked with their products. Again, if I understand you, the switch needs power, probably from mains, however the wires that go back to the sub panel are passive and probably need to be isolated from mains in the switch. Below is a board I have experimented with that might be be able to do what I am describing above. It is far from ‘UL’ approved however. Good hunting!

Unfortunately we’re quite limited in our choice of suppliers, and that product doesn’t appear in any of their catalogues, but in case an opportunity for an outside purchase comes up, I’ll keep that in mind!