Your watch needs to be connected to the same WIFI network as the device your trying to connect to most times. Problem is, watch when paired and connected to phone, turns off WiFi automatically. You'd need to turn off Bluetooth and connect to wifi directly from watch, then see if you're able to can connect to the Home device.
Another possibility is that watch can't support the interface required to connect to the particular device. Even in the play store version of the Home app, some devices can't be controlled from watch, and instead opens the interface on connected phone.
Also keep in mind, the Home app serves as a middle man between you and your devices. At a minimum, it displays the status of your devices. However, when you try to connect directly to a device, it requires specific software and connection compatibility to do so. Older android versions have limitations with newer software. Our Galaxy Watches are like running older android versions. Watches have nowhere near the compatibility our smart phone do. You could also see if you can get the latest version of Home app from ApkMirror to run on watch. The one in OP is old because I believe newer versions crashed.