(BTW this isn't the official company sanctioned sub, insofar as they have presence on Reddit, it's not here)

I don't have experience with these products, but here are my thoughts on related system architecture:

• I would caution against going all-in on their bulbs, or any products for that matter, without reliability testing. I have two of their Pro 12W E26 bulbs (https://www.amazon.com/GLEDOPTO-Dimmable-Compatible-SmartThings-Lightify/dp/B07QXS64WB?th=1). Even with two bulbs right next to each other, they get wedged at least once per week, requiring a power cycle of the circuit (fortunately I have things setup to make this less painful). Gledopto has no firmware update policy so I'm stuck with this flakiness.
• I don't see why low voltage would imply "not a router". I can see that battery-powered would imply "not a router". For instance, the Gledopto Pro low voltage LED strip controller (https://www.gledopto.com/h-nd-143.html) is a mesh repeater and it's low voltage.
• I believe Gledopto will answer your questions about the difference on their platforms [I've seen them answer before, can't remember where], you can try @'ing their official account or asking questions on Amazon/AliExpress. I think some of the versions do not have Zigbee repeater.
• What your blocker for installing routers? If you can find the right module you can power it from low voltage with the appropriate voltage controller bundled with it, sealed in a IP6X PVC box. They survived getting sprayed by my sprinklers a lot longer than they survived my squirrels chewing on the cables. That's what I do with esphome nodes in the garden. I guess the hard part is finding a zigbee router that's low voltage and has a solid firmware.