Anyone had experience or seriously looked into freezing a reproductive egg (ovum)?

You may want to look at this article. It does not sound promising. Only two in 100 ova are viable on thawing, and they haven’t even been fertilized or implanted yet. You can maybe produce as many as 20 eggs under a stimulated cycle, although more like 10 or 15. You might go three cycles to generate enough eggs to give you a good chance of having one survive thawing. It also costs around 10K per cycle, plus storage costs (upwards of $1000 per year) and insurance pays for none of it, because it’s still experimental. Finally, there are mores risks to it, apparently, but read the article to find out about them.

I wish you the best of luck. I hope you have the child you want.