Is the up relay picking ? And also do you have voltage at the valve coil? Is it an mph1 or mph2?

What valve? Did you check to see that your relays are seated properly? You could have burnt contacts on relays

I changed all the relays. No voltage coming from the board to the valve coils, but only periodically

Remove the Schindler and install a Smartrise hydro controller instead.

When there's no voltage to the valve coils it may be running on viscosity? Do you have an HHT or other diagnostic to plug in?

I think I’d consider that more of a lateral move than an upgrade.

It's barely lateral but I think you're correct lol

Check your Delta relay 11T

is this Alex guy for real , he is a joke !

He worked for them and is a salesman. We all know about salesmen.

Whatever yu do, don't install SmartRise. Smartrise is dooky! I mean it! While I'm not against mods, many of the little family owned independent companies just like to target old equipment for mods by using the "obsolete marketing trick" to trick customers into unnecessary mods, stating that parts are no longer available. They tend to target reputable equipment from the major OEMS like DMC & MPH. In many cases, that's not always true. Before considering modding, do your research on part availability. Depending on your hardware and controller, some individual components can be modded/upgraded such as just the door op. without having to mod the whole thing. If you had to do a mod, I would recommend MCE or EC. Both have been in business a long time, and the reliability is much much better.