Android phone hotspot to iMac

I connect an Android 7 phone to a 2018 iMac running 10.13.6 via Hotspot with the Automatically Join setting on. It used to auto connect for a while after a Shut Down and connected less after a restart (earlier versions of 10.13). Now it only does it once before I have to always select the network name from a list.

My wife has the same make & type of phone and connects via hotspot with a different name, but not at the same time. We have no landline. Same problem.

After many discussions with Apple, they state that this is so you don't accidentally connect and use your data allocation without knowing it. Could someone either confirm this or otherwise, because I don't believe it.

I would especially love to hear from anyone using a similar set-up and if it auto connects or the same as me.

Thanking you in anticipation.