Well yeah but no self-respecting developer has done this for 15 - 20 years... it's kind of a red flag these days!

I really wish this was true. Sadly the caniemail website - https://www.caniemail.com/ - says that Gmail still doesn't support CSS grid or flex, which leaves nested tables for layout as the only viable solution for HTML emails (which, however many times you plead with your marketing colleagues, is still their preferred way for contacting/stalking customers).

people say this about inline styles too but Notion built a 100 million user business with them ¯\_(ツ)_/¯