Not even considering the stick has been announced just yesterday, if you already have a zigbee stick, why would you want to migrate to a hybryd/hacky solution like SkyConnect.
I mean, having dual radio is fine to avoid buying additional hardware (although it still has to be seen if it will actually work fine, without caveats), but if you already have the hardware and a working setup, I don’t see the point…
If you get some usb extension cables you can place them as far away from each other as you need. Which is best practice anyway if your device has any USB3 slots as those seem to cause massive interference.
Assuming that the Home Assistant SkyConnect USB adapter is based on an Silicon Labs EFR32MGxx chip and depends on zigpy/bellows libraries then if you are using ZHA it will be compatible with the upcoming zigpy-cli Zigbee network backup/restore utility that will be implemented using the new radio API for zigpy and will initially support Zigbee network backup/restore for Silicon Labs, Texas Instruments, and deconz (ConBee/RaspBee) based Zigbee adapters, and thus also migration between those radio types:
You should however know that while the upcoming official Home Assistant SkyConnect USB Stick will be great for early adopters of those wanting to buy new devices using the new Matter/CHIP standard over Thread protocol, that upcoming official Home Assistant SkyConnect USB Stick should on paper actually performs worse with a large Zigbee network if you will use as a multiprotocol radio with Matter/CHIP over Thread in combination than if you instead buy and use a other separate dedicated Zigbee USB dongle based on Silicon Labs EFR32MG21/EFR32MG24 or Texas Instruments CC2652P/CC1352P. This is totally understandable considering running two protocols over, even with the off-loading to System CPU it will do, will not perform as well as a single dedicated modern MCU/SoC that has purposly designed firmware for Zigbee.
It is the jack-of-all-trades but master-of-none dilema. That is unless you either have plan to not connect loads of devices in total or buy two of those SkyConnect adapters to run one dedicated for Matter/CHIP standard over Thread protocol and the other dedicated for Zigbee, otherwise if you plan on connecting 100+ devices then it will be better to get a dedicated adapter for Zigbee.
So instead consider just buying a separate dedicated Zigbee USB dongle now to use only for Zigbee devices, and then if you want also buy the official Home Assistant SkyConnect USB Stick when it comes out and use that only as a separate dedicated for Matter/CHIP over Thread.
That way you get the best performance and still sponsor Home Assistant by buying their dongle.
My point is, there is no point in waiting for Home Assistant SkyConnect USB Stick if want to use Zigbee today as it is a jack-of-all-trades that for Zigbee specifically will not perform better than existing Zigbee adapters that use a modern radio MCU SoC and has an external antenna.
Therefor I today recommend Sonoff-branded “ZBBridge-P” (for Zigbee2MQTT) and “ZBBridge-E” from ITead as a dedicated Zigbee Coordinator adapter (those cost less than $20 and have similar specifications and either will work great with the ZHA integration as long as use long USB extension cable and connect to a USB 2.0 port or powered USB 2.0 hub. Additinal adapters of the same model can also be used as Zigbee router devices for signal repeating to increase range and coverage. See:
Yes USB 3.0 as well known for causing serious interferance to 2.4GHz radio and low-powered radios like Zigbee, Thread, and Bluetooth as known to get loads of issues with reception when close it USB 3.0 devices and their cables.
If your computer only has USB 3.0 ports then the general recommendatioin is to buy a powered USB 2.0 hub and connect that to the computer and then the (long) USB extension cable to it, as the USB 2.0 hub will convert USB 3.0 to USB 2.0 so therefor remove the interferce caused by USB 3.0 before connecting the Zigbee Coordinator radio adapter via a (long) USB extension cable that will place it even further away from interference.
Using a “powered” USB 2.0 hub with its own external power supply will secure the power requirements for the Zigbee Coordinator radio adapter.
See more generic tips here best practice tips on improving Zigbee network range and general stability:
I definitely want to switch to Skyconnect. Now have deconz conbee2 and it suck’s big time. Range is terrible and it keeps losing my devices and I have to reconnect them again. Hope this stick has a better range and is stable