I wanted to post this in case it helps someone else. I recently found some additional configuration on my UniFi that has stabilized my Wiz WiFi bulbs.
A few weeks ago I started having trouble. I had not changed anything. I had been stable for years. My Wiz bulbs started taking forever to respond, if at all. Bulbs would go offline in the Wiz app and in Home Assistant. All day, Unavailable then back online.
I have a WiFi SSID, IoTWiz , that is set only for 2.4GHz. The Wiz bulbs connect to that and have been stable until now.
Back in the day I did a complete WiFi site survey of the house using purchased software on my Mac. Based on that I set the UniFi access points to a transmit level that was appropriate.
Here are the three changes I made. What a difference. It was INSTANT stability.
In UniFi, Settings / WiFi / IoTWiz (the ssid network for Wiz)
Checked UAPSD
In the same section I set a Minimum Data Rate Control to 12 Mbps.
Lastly I went through all of my UniFi Access Points and looked at the Transmit Power. Based on my original site survey I needed a few of them to be on High to get good coverage. I changed each one to a maximum of Medium.
The access points were already configured to not overlap too much the Channel from one to another based on my site survey.