Adding a second hub 2 router to our garden office, advice needed please....

[#1]

A tip that will probably upset the 'experts' on this forum, set a different SSID name on the new device in the garden office to the one on the router but keep the same password........

Why is that contentious?

[#2]

It’s not.
A device will connect to a local  AP and is reluctant to change until the WiFi signal is no longer within range. The effects may not be noticeable within the property but being in a garden shed the device could still be connected to the first AP resulting in a terrible connection and a lot of head scratching. Using different SSIDs the user can quickly check the connection and make changes when necessary.

[#3]

It's a marmite question.

Having the WAP and router sharing the same wireless name allows for seamless roaming. Just need to make sure they use different channels and the selected channel does not overlap.

There's always a but, some newer devices may prefer WPA3 to WPA2 so they might cling onto a weak WPA3 signal over a stronger WPA2 one. WPA3 might need enabling before it's used as sometimes WPA2 might be the default setting.

Not been a problem for me for years having the same wireless name.

[#4]

If all APs are using the same SSID how do you know which one you're connected to ?

[#5]

If you’re using the same SSID across multiple APs then the configured security method should be common. Some clients will grumble if they see the security mode change for a ‘remembered’ SSID, particularly if it’s demoted from a WPA3 variant to something lesser.

[#6]

If all APs are using the same SSID how do you know which one you're connected to ?

For me I check the router connected devices page, a device will either be connected locally to either 2.4 or 5 GHz  or in the case of the AP to a LAN port.

It's a choice how you do it, no right or wrong answer. 

EDIT: usually the device connects to the AP with the strongest signal strength