English IS the lingua franca in Europe, right now, at this moment, no question about it. Even the in remotest parts Generation Z and younger speak and understand a little bit, it is only the older folks who still remember the EU with borders are reluctant to speack anything else other than their own language.
And there are more and more people picking up a third language as they move around within the EU.
English is well suited for this lingua franca thing because at the beginner-to-mid level the syntax is simple, and you can get by with a few hundred words, much better than in other languages. Also there is a common pronounciation that is different for everyone (and reflects the mother tongue of the speaker heavily), but again, people speak slowly enough that it is possible to understand what they are trying to say.
Which cannot be said about the native speakers (coming from the UK, mostly), so the UK leaving us might actually improve the situation. No more awkward meetings where 20 people understand each other reasonably well, but not the single UK representative... (true story)