I’m not sure where this myth of seamless hand-offs comes from but it’s impossible to drop one radio signal and pick up another without interrupting the transmission. There are protocols in place that buffer the data but VOIP and WiFi calling will still often drop if you wander around and change your connection point. And that’s with any multi-station WLAN system.
That doesn’t sound like what’s happening here though. It sounds like the phone has decided that the 5G signal is a better bet than the WLAN so it drops it until it decides WLAN is better again. Which is what it should do. It’s what it does when you leave home, or the office.
I suspect the WLAN coverage isn’t as good as the OP thinks it is.
When I had the issue described, the WiFi icon would disconnect, 5g would appear then about 2 seconds later, WiFi would reappear.
When this was happening I used the signal meter app to move between nodes and the signal would start good, move down in strength and then drop completely. Big gap in the chart then it would reconnect on the other node, and strength would be good again.
Since I resolved my issue none of that happens. I can move around, wifi remains connected. And using the same signal application I can see the hand off between nodes occur and there is now no drop / gap in the process. Unlike before.
I can be in voice calls (real-time traffic) and transition around OK on WiFi. No loss or drops or changing over to 5g. So for me and from what I can tell, it is seamless. Having owned 2 prior mesh systems to this one, it certainly never acted like that before.
I wonder as you say though, if the OP potentially could have a dead spot where the range isn't overlapping enough between the nodes.
EDIT: Here are some screenshots to help explain what I was seeing, mentioned in my post.
This is the handover, as of now, with everything working OK. WiFi does not drop. This is me walking from one end of the house to the other and the handover between the two nodes (554 > 004) about halfway inbetween.
And this is what happened when it did as the OP describes. Note the big empty gap. That was the WiFi disconnecting, 5G connecting, then WiFi reconnecting. Which shouldn't happen (works as shown above).
