Many of us who follow a low carb way of eating to help manage our diabetes use real butter and real cream and full fat milk and cheese.
Most of the spreads are heavily processed and not necessarily better for us and don't taste as good as butter in my opinion. If I am giving up a lot of the things I used to enjoy, then I want to enjoy the foods I have left to me in order to make it sustainable, so I have real double cream in my coffee on a morning (never Elmlea) and it is one of my little daily luxuries and a knob of real butter on my cabbage and courgettes and mushrooms etc. and a chunk of really nice cheese for lunch with half a good British apple like a Braeburn or a Coxes if I can get some, or one off my own trees, cut into slices instead of biscuits or grapes with my cheese.
Good to hear you are getting more consistent readings from your meter. As mentioned, a replacement doesn't have to be more expensive but just one that is known to be reliable. There are 3 on the forum which are all much the same price as the one you bought and have reasonably priced test strips, but are tried and tested by members here over the years without issue. Those are the Gluco Navii, the Spirit Healthcare Tee2 and I think the Contour Plus Next. Hopefully someone will correct me about that last one, but the first 2 have been used by members here for many, many years without issue.