Watch 4 (WearOS ?) cannot be detected unless settings->bluetooth screen is on

[jeffgoh]

I was able to use monitor with my previous generations of Samsung Galaxy Watches, but not with the new Watch4.
I'm not sure if it's a generic WearOS issue (previous generations of watches were Tizen)

Settings->About Watch->Device->Bluetooth address on previous Galaxy watches (Watch, Active2, Watch3) but
Watch4 seems to have locked it down (not a bad thing, other than it's useless to trigger a HA automation).
Settings->Connections->Bluetooth puts it in some visible mode (discoverable? pairing?) mode
at which point hcitool scan is able to detect the watch mac address.

At this point, everything seems perfect, but a few minutes later, the watch is no longer visible to monitor and gradually returns to confidence = 0. hcitool confirms this too.

I don't believe this to be a problem with monitor per se, but at this point this watch will not serve the purpose of unlocking my front door, which is a very handy automation I miss.

Any suggestions as to how to keep bluetooth discoverable on a Watch4 or WearOS3 device?