So short version, your devices use repeaters to make your network stronger.
But honestly I don’t see enough repeating devices of any one type (ZigBee or ZWave) to form critical mass for a working mesh for either protocol.
- Hub - both ZWave and ZigBee no problem here except being a V1 hub. Not supported by firmware updates anymore.
- All your various multipurpose and motion sensors, ZigBee… Ok, But they’re battery powered so none of them repeat signal.
- FA Smoke. ZWave, will repeat, ok.
- Schlage lock. - ZWave, battery powered, wont repeat and additionally NEEDS a beaming capable ZWave repeater nearby (dont see one) for best performance.
- Cree bulbs - these should theoretically repeat for ZHA profile ZigBee… See @JDRoberts post here Bulbs as network extenders. Are they repeaters or just receivers?
- But to be totally honest ive never had any luck with bulbs being decent repeaters (and I don’t use Cree bulbs - I use Sengled when I need one SPECIFICALLY because they don’t repeat and I have better control over my ZigBee mesh)
- Finally your Hue bulbs. They repeat for each other, but wont participate as a SmartThings ZigBee repeater.
So for ZWave, you have only one repeater and for ZigBee you have very few known reliable repeaters. (your Cree bulbs are having to carry the load and again, i dont trust bulbs as repeaters.)
My best guess here is anything that is farther than ~30ft. / ~10m from your hub drops… A lot. Unless your ZWave devices live close to the hub, those are always giving trouble and your ZigBee stuff like the bulbs and sensors drop randomly… But when a bulb close to the hub drops you lose large chunks of your system. It may not be as bad as described but I’m sure I’d be going batty chasing issues…
To fix this youre going to need to evaluate installing mains powered repeating devices for both ZigBee and ZWave about every 20-50 ft., working your way out from wherever your hub is.