ZigBee is already so widespread that I don’t see it going away. I’d be much more worried about your WiFi devices.

While WiFi as a network technology certainly isn’t going anywhere, most WiFi-connected devices talk to a service on the internet. You probably created an account somewhere to manage your WiFi devices. So if the manufacturer shuts down their service, which happens all the time when they either shut down the whole business or abandon a product line, you will have no way to manage your devices.

ZigBee will continue working as long as your hardware does, because you control the software managing it.

Have you considered just putting the lights in the same group? If you can make your switches control the group you should be all set.

https://www.home-assistant.io/integrations/group/

You might also be able to link them together on the Z-Wave/Zigbee level, depending on your hardware.