hatchmo

I solved this by simply copying the plugin’s folder directly to the WordPress plugins directory. This was necessary because the installer always unpacks the .zip file improperly. Whether that is the fault of WordPress or of Akeeba, I will never know.

• This reply was modified 5 years, 3 months ago by hatchmo. Reason: Typo

Success! The challenge was to find out first that I needed php7.x-mysqli, then how to install it.
I have to tell you, I read nearly 500 posts about this online, all full of misinformation (in particular about WordPress). Yours was the only response that directly answered my question and actually helped.
Thank you!