How to stop stop updating to ventura?

Hello

My machines are too old to use Ventura, and in any case I'm happy with what I get and what I do-

ALSO THE Upgrade to Ventura is not an update but a COMPLETE change from the previous intel Machines.

Yesterday I installed by mistake on a former HIGH SIERRA macbook air and to revert to HIGH SIERRA I spent a number of hours. The Server kept asking me to Reinstall Ventura on the standard RECOVERY page until I decided to erase everything and make the computer as a WINDOWS tool.

I know nothing about WINDOWS but I called a friend who helped me to fully erase the MACBOOK and eventually I was able to install Mojave with an USB KEY he brought along with him.

However again I had to create an external USB key with HIGH SIERRA installer and finally I was able to get back to my stuff.

Since the Ventura installation was a mistake I didn't have a full backup of my stuff, hence I lost a lot of work.

As you all know the Ventura ICON is on top of the page. I clicked it and it was my mistake, but I was unable to stop it as at the very same time I received a call on my landline which is elsewhere in my house and had an important and long work call. I didn't realise I started the install so when I came back it was all done.

MY QUESTION:

Is there a terminal or another way to stop the little update window to offer VENTURA as a first option or actually disappear altogether?

VENTURA might be great, but I pay good €uros for my machine, for the software I purchase, and for the time I spend working. Apple should not be allowed to force its user to follow their commercial need.

Any help will be totally appreciated