I would not try to paint that fireplace except as a last resort. Spray can paint will almost never achieve a factory look, is not as durable as factory paint, and you'd have to take the whole thing apart to do a decent job. Any attempt to paint it in place is going to be an obvious hack job.

I would try going at it with this stuff and plastic scrapers / paper towels. I don't think this will dissolve the original paint, but test a hidden part of it first.

https://www.amazon.com/3M-General-Purpose-Adhesive-Cleaner/dp/B0002NUO6K/