Tesco on line was brilliant when lockdown started, they were the only delivery service I could secure, their website is excellent and their drivers all very good. Problem is I don't like a lot of their stuff. However, they are quite good for wine and I buy the occasional book, so those items make up my order to £40. I wouldn't be prepared to pay £4.50 for a delivery because I'm not far away from supermarkets and don't waste a lot of petrol getting to them. I understand the point of view of those who live further away from shops and set off the delivery charge against what they would spend on petrol. I'm lucky I have a very good Marks nearby, larger than the average Marks local, I can get in there without queuing around 9.30, it's quiet then, so I go there for meat, fish and some vegetables, quite honestly for some things they can be cheaper than Tesco surprisingly! Before the lockdown I did shop at Sainsburys quite a bit, pretty good for bargains, but I wasn't too impressed with their on line service, not so keen on their website, Tesco has a better one and some of the products they supplied had a very short sell by date.
I've missed Waitrose, getting my first delivery from them next week, no charge but a £60 spend required, probably not the best for bargains, but better quality usually.
We have a new Aldi that opened just before lockdown, haven't tried it yet, but my son who lives near where it is, tells me they are very competitive on price and generally, I know from using a smaller one, the quality is often very good.