Through my entire stint having to use it in Europe, the closest I could find was a webview for the web client: https://f-droid.org/en/packages/io.kuenzler.whatsappwebtogo/

Sadly, they enforce use of the official client to create an account and resync whenever the web client session expires. Even once got locked out for using the official client downloaded from Aurora Store, apparently I ought to have to downloaded the APK directly from their website, if not from the play store.

Edit: I also think potential legal pressure also contributes to a FOSS client not existing. Last time someone tried making a feature-complete FOSS Instagram client, they stopped after a cease and desist from Meta.

Obligatory, I would have loved to go without anything Meta in the first place, but if you've spent any time around non-techy colleagues in Europe, you'll know how much of an uphill battle it is.