@Inetdad I was pleasantly surprised by your posting. I also found a new version of TpPlc on the TP-Link site. But unfortunately I do not see your 'arrow' yet.

I installed the latest TpPlc on another Windows10 computer and that did not make any difference. I noticed however that the powerline adapter names are still local to the computer that runs TpPlc

@JanLunteren 
OK, I still use the utility extracted from the PowerLineUtility_Win_180816.zip file... So it is version from August, 16th 2018.
And thank you, now I see there is a very new version dated some days ago!
I will try it and hope switching the networks is now better (with the old version I can switch, but the network name does not change - so changing something on the 2nd network is very tricky...). 

@Inetdad Ok, I will experiment a bit more. Sometimes the second network is quite weak and it might not get picked up by TpPlc. 

@JanLunteren 
New experience with tpPLC latest version (from end Nov. 2020):

1. network (security) names of the different networks now is OK when switching

2. switching only works if PC (Win20 pro) has 2 different connections (in my case LAN + WLAN) established direct to router 
--> did not test if LAN to router and WLAN to an TL-WPAxxx also works)
--> my LAN interface is from motherboard - the WLAN is from an Intel PCIe card with WLAN 6 and Bluetooth 5 --> no idea if this matters (router is docsis 3.1)

3. switching does not work using a USB-Stick 3.0 for WLAN (instead of the PCIe WLAN)

4. switching does not work when using mixed network speeds (e. g. first adapter connected to router with 1.200 mbps; second with 2.000 mpbs)
--> as with old tpPLC version only the network with higher speed is shown! 

--> I used this TP-Link equipment:
first try: 1st plc network PA8010P connected to router / 2nd with PA9020 to router --> tpPLC does not switch the networks
second try: used PA8010P on each networks (of course with different security (network-)names - as in frist try) connected to seperate LAN ports of the router --> switching is OK!

@Inetdad 

Thanks for your test results. I certainly have different speed for the base adapters PA411 and PA8010. I will exchange one of those for an equal one and see what happens. I'll let you know. I'm quite busy now. So it can take a couple of weeks.

@JanLunteren 
No problem - I am retired... and have planty of time!  😎 

@Inetdad . Thanks for your patience. I recently tested my two different powerline networks (both encrypted) using the same device types (the older av500) as the wired base stations.

I still do not see the arrow to switch between networks, but the view in the TpPlc utility alternates every now and then between the two networks. So the test more or less succeeded.

I then switched back to my previous base station because it has higher specs (TL-PA8010) and found out the the view in the TpPlc utility still alternates every now and then between the two networks.

I'll leave it as it is for now.