Is it bad practice to have the main language in WordPress in English, but main target audience in is German?

My WordPress website is available in 3 languages: English, German and Spanish. My main language at domain level is English. But my target audience changed with time. Now, I target mainly German-speaking people. But my DE language loads in a /de URL. Is this a problem regarding SEO best practices? I use Polylang, with setting to serve the language of the system/browser and language flags. However, in analytics, I see that many people from Germany are landing on English pages. Thanks for your help. Sebastian