OK, after restoring and a brief night of testing at home… strange results.
I’m connected to my home WiFi (T-Mobile 5G home internet - tops out at 500mbps but currently testing at 300mbps from a laptop), and… it’s weird. It at least stays connected! But … it seems to be putting all my data through LTE instead of WiFi. If I Google “what is my IP”, I get a different address on my phone than on my laptop. Hard to tell which is which, since both are T-Mo, but yeah! It’s piping everything through phone data instead of WiFi, though WiFi shows connected with no alerts (e.g. doesn’t say “limited connectivity”).
Apps act very erratic - lots of hanging/loading swirly. Speed test from web browser shows 4-5mbps download.
This is on a fresh factory reset, too. That’s a bit odd…?
I’ll try rebooting (haven’t rebooted since the initial setup/restore), but that’s worth noting.
update: Same story after rebooting. Shows it’s connected to WiFi, but different public IP vs. my LAN computers, and speed is LTE-speed.
The plot thickens. I go to http://whatismyip.host and I get the same IPv4 between phone and laptop. But for ipv6, it’s quite different. I wonder if this is an ipv6 vs ipv4 routing issue, and ipv6 is getting routed through LTE. 
IPv6 is weird and I can barely begin to understand it, but I’m familiar with ipv4 mechanics (at a LAN scale at least - subnet and routing is the boundary of my knowledge). So… maybe an issue in that department triggered the new beta to go haywire?
Just getting really weird results from different speed test providers. Google shows 4-5mbps even when airplane mode is on (with WiFi enabled - thus forcing WiFi) - but I see the same on my laptop, now that I tried that too. Other tests show 100+, but strangely, high upload speed as well (60mbps+) - as I’ve regularly tested I was getting dismal 3mbps normally. It’s all over the place. This all might be a red herring due to the weirdness of T-Mo’s new home internet service (I love being a guinea pig and paying for it - only half kidding, lol).
So, tl;dr: let’s just chalk this up as “it works fine in the old version 6”. So far, no physical connectivity issues, just … weird routing issues probably inherent in my home internet. I had no trouble at work today after the restore. So let’s go with that!
