I think you have the same problem as me @Kivanc_Cubukcu, which I wasn’t able to solve.
If you can’t extend your Zigbee network by putting some more routers in between, your best shot is to create a second Zigbee network and import those devices into Homey, but you need network in your basement then.
If not present (and wifi doesn’t reach that far too), you might try two powerline adapters to connect the basement to your home, network-wise.
The you need a hub, like Hue, Ikea or another Homey. An Aqara/Xiaomi hub is possible too, but a bit more tricky.
There are Homey apps for importing devices connected to those hubs (for Homey you can choose between Homey Link, webhooks and Homesh).
Check first if all devices you want to connect are compatible with the hub of your choice.
Hope this helps you a bit, search the Community here for further explanation. There’s a lot of info to be found here.
