I use an iPad Pro on solid WiFi and have found much the same thing. Big drop off in speed several months back and none of the updates make it better. My iPad is a couple of years old. I’ve been an Evernote (paid) power user since 2009, but when it takes 30-40 seconds just to open the app, it’s unacceptable. If I’m trying to jot down an idea, I’ve forgotten it by the time the app opens!