I've been using a Raspberry Pi 3+ using Ethernet to my router (not wifi), Home Assistant (Hass.io version) and Node Red for a while now. It did take a bit of learning but not really that hard. Just some reading and youtube videos. It is well documented.
With Node Red it is very similar to stringify only way better. I have created flows that would have been difficult or not possible in stingify. My flows work with my insteon hub, lifx bulbs, smartthings hub 3, tp-link, rachio, ring doorbell, google calendar, sonos music and iphone location.
The Home Assistant took me a few days to get everything setup. But now just runs as another hub. I don't really do much with it but let it control things. Node Red does all the triggers. It took a few days to get some flows going but now it is so easy. Just like stringify it took some learning but way worth the effort. Flows for me take no longer now to create in Node Red then it took me to create with stringify. Editing and debugging flows in Node Red is way easier then stringify. You can copy and paste nodes (things) and delete node connectors without having to start over.
I have a flow that uses a smartthing multi sensor's temperature monitor to turn on or off an insteon ceiling fan controller. When the temperature rises above or drops below a certain temp the fan turns on or off. The flow also turns the the back-light on my insteon 8 button switch so the switch that controls the fan stays in sync with the fan setting. Could not do all this with stringify.
My flow that turns on my porch lights used to have a delay using stringigy. Now the lights turn on the instant the door is opened. And the timer that truns the lights off resets if the door opens again. This took two complicated flows in stringify. Only one simple flow in node red.
I am so pleased with this setup. Yes it took a bit to setup but now it just runs and I don't think much about it. This setup is fast and rock solid now. I have all my stringify flows setup and running on node red and a few more flows. So worth the effort.
Now I have something very similar to strinigy only way better IMO. I have not seen anything else that is close to stringify other then node red.