When using any font CDN, keep these tips in mind to prevent "Flash of Unstyled Text" (FOUT): Font Licensing Extortion - Futura - Bauer Fonts : r/webdev
Since no legal Futura CDN exists publicly, most designers use that have a similar geometric feel. These are available via free, fast, reliable CDNs (e.g., Google Fonts, jsDelivr, Fontshare).
Futura was designed in 1927 by Paul Renner, a renowned German type designer. At the time, Renner was working for the Bauer type foundry in Frankfurt, Germany. He was tasked with creating a new font that would reflect the modernity and simplicity of the Bauhaus movement, which was gaining popularity in Germany during the 1920s.