1. Find an old Android device (Phone, TV, tablet etc.)
2. Factory reset.
3. Create a new Google account.

Of course not. The point of their accounts is to lock you in their ecosystem

I don’t understand what’s stopping you from creating as many free Google accounts as you please. https://support.google.com/accounts/answer/27441

If you mean an anonymous account from an email service trusted by other online service providers, it's not possible to get one for free. Even among paid email providers, very few accept anonymous payment methods such as cash or XMR.

What is a dummy account in this context?

I have about a dozen accounts i rotate between using when i hit usage limits on cursor and other ai junk. I did pay for them but they cost like $2 each

You can create new Google accounts via Gmail on a phone (not on desktop) I think you go to settings -> add account and then create new account or something like that

Proton offers free tier.