I don’t run v5 so can’t comment on it, but I don’t use Homey for Zigbee (or home automation) in general anyway
My experience with the gateway (more than a year ago) was pretty good, although every few weeks or so it starting giving issues and I had to reboot it. After a reboot, it worked fine for a few weeks again.
Make sure that the gateway has a fixed IP address in your network. I don’t think you can configure that on the gateway itself so you have to do that in your home network’s router (give it a fixed IP address in the DHCP settings). Otherwise the IP address may change and the app can “lose” it.