The case mentioned in the article was taking 5000 IU/day, and that proved to be too much. I'm not an expert, but 10000 sounds a WHOLE lot.
I started taking 2000 IU/day because I wasn't seeing much of daylight because of the pandemic. I hope that's a safe amount, but it would be nice to get my blood levels checked.
There are a fair number of clinics that will do blood tests for you. This is the first one that came up on DDG: https://www.everlywell.com/products/vitamin-d-test/ $49 but you have to prick your finger for the blood they need.
I started taking 2000 IU/day because I wasn't seeing much of daylight because of the pandemic. I hope that's a safe amount, but it would be nice to get my blood levels checked.