Embassy size doesn’t correlate with power. This is easy to observe in various European countries, where the Russians managed to hold on to their huge Soviet-era embassies, even though their contemporary influence is far lower.

To be fair "Embassy Row" is just a road with a lot of embassies. Embassies and consulates are all over the place in DC.

I don't feel like this answers the question. Saudis have outsized influence on the US because they have a large building as their embassy?

There is a really interesting dynamic where the Saudis have basically pushed the line of thinking that they have a special relationship with us going back to WWII or WWI. I generally am a bit skeptical of Cato Institute but they had a great podcast with Prof Robert Vitalis about this that shed a ton of light on exactly this question for me. https://podcasts.apple.com/gb/podcast/americas-oil-myths/id1...

No: they do it the old fashioned way: lobbying and political contributions.