We were bought and now the parent company wants to add monitoring
software to our personal computers.
That sounds completely wrong to me. Using personal devices for work is already borderline in my eyes. And I don’t even see how you can guarantee your privacy. Try to get some information about that monitoring software but it probably has Teamviewer-like functionality built-in, meaning that they could literally see your screen and watch over your shoulder. I would assume the possibility exists. Let’s hope they are not talking about this nasty piece of software.
Seems to me that your employer has a duty to provide equipment, and there are also legal considerations too, but I can ‘t really comment on that. At the very least, the employer must provide full disclosure about what the monitoring involves.
I am not familiar with Mac computers, but maybe a dual boot configuration is possible, so you can switch between personal and private setups and maintain isolation ?
I guess there is no trade union in that virtual company either ?