Ask your boss for a sit down meeting because you’d like to have a performance review since it’s coming up on a year. A one-year performance / check-up review is a pretty standard thing. Asking in person is best because if he doesn’t really want to it’s harder for him to put it off than if you email him.
Once you sit down with him, start out friendly with a minute or two of small talk, then ask him what he thinks of your performance so far this year. How positive or negative his assessment is will give you an idea how successful your raise ask is going to be, and will give you some thoughts for how to adjust your talking points.
When it’s your turn, talk up all the great things you’ve done for the company and how you’ve saved them money and gone above and beyond, as @Dewey_Finn said. If your boss had negative points address them without being confrontational, either explain why you respectfully disagree or explain how you will improve, depending on how accurate he was. Explain your plan and vision for how you will improve the company in the coming year.
Finally, mention that you took the job with the expectation you were on a 3-month trial period, which understandably got extended because of the pandemic, and people in your position typically make $X yearly (again, @Dewey_Finn is right, do your research), and you feel you deserve a raise to $X amount (ask for more than you think you’ll be able to get, because your boss will probably compromise on a raise). Don’t be intimidated! If you do a good job for your company you absolutely deserve to be paid what you’re worth. Managing 500 properties sounds like you have your hands full with that job!