Except the tests you have to scan a QR to register, get the result by email etc.
Sure it's "possible" but then you have to take a photo of all QRs of all the test centers you might want to use, register for those at home, go there, go home to print the email. Rinse and repeat every day.
So you could do that and waste 3h a day doing it, or you carry a phone.
The registration in restaurants a lot of restaurants don't accept paper registration anymore either.
Fortunately have never had to show a test or a vaccine pass on a phone. Boy am I glad I’ve been living in England these last few years if that’s becoming normalised!
You can do all of that without a phone.