It's not always possible, but I buy British as much as I can and do my shopping in real shops as much as I can, and when in supermarkets, I go to a real cashier as much as I can. Also, I pay in cash as much as I can.
These things are not always possible, and when they are possible they may cost more and be less convenient.
We have destroyed a lot of what we had for convenience and a quick profit. Just look at your own signature Securespark.
You're partly arguing against technological progress. I appreciate not everything is considered 'progress' by everyone depending on our own views, but overall it's a tide we can never go against as a population. Yes some people can (e.g. taking an extreme example those that live off-grid) but not the average person who's simply getting on with life.
Full disclosure, I love the convenience of Amazon, and you can often find stuff you'd struggle to find in a local shop. Plus it's great, as is all online shopping, for those who either can't leave the house or live quite far from shops.
I also love the convenience of 'scan & go' or whatever it's called in the supermarket. I can pack my items as I want whilst completing my shop, then quickly pay and go unless stopped for a random 'quality check' which isn't very often. I've seen quite large queues at the traditional check-outs and the scan and go section relatively quiet. Maybe folk taking a leaf out your book. I'm walking out the store whilst the majority of them are still queuing, often looking miserable.
As for buy British, are you having a laugh? Possible for some things, impossible for many. We've given up on most of the industries we were once world renowned for. Up here in Scotland we can't even build a couple of ferries on time or budget, so the next couple are being built in Norway or somewhere like that.
There are many small to large examples of 'progress' that I dislike e.g. cars becoming ever more like mobile IT devices, electronic parking brakes etc. Ultimately can I stop it? Nope.