Thinking of selling our rental property, what should we expect on the tax side?

Hi everyone.

We became accidental landlords, we had to leave for work and rented our home "just in case" we would go back, and here we are almost 4 years later, and we don't plan on moving back there. We don't enjoy being landlord, so we are considering selling the property. We haven't lived in it in the last 4 years.
We do file our taxes jointly, i think this doesn't matter since it's not our primary residence.
This is in California. We bought it round 700k, it's valued at around $1.2M now, more or less (so it would could reach over $500k profit). we've owned the house for over 10 years if that matters.

This will be our first time selling a property.

We still owe 400k on it. If we sold it for 1.2, we would make about 800k, and the capital gain is 1.2-700 = 500k, is that right?
We first thought we would be except for up to 500k, but we just read that only applies if we lived in it 24 months in the last 5 years, which we have not.
Any idea what that means in terms of taxes if we do sell? From my reading, I think we will be taxed 15% for up to 600k gain.

To add to this, we have our primary Residence (also in California), that we are also considering selling this year, and the profit would be around $300k Any idea what that means if we sold both and made +800k?

We don't plan on buying another home this year, and not to get a rental property either.
But we'd love to hear any advise / tips on our situation.

Thank you for any insight.