Exercising outside away from people such as walking should be fine. I've never heard any proof that you can get Covid just from walking down the street not near other people. You could always drive to the countryside where no one is around for walks.
As for groceries. Order them online. There are meal delivery services doing prepackaged meals. Or you can pay someone to go get groceries for you. If you are in a high risk group it would be worth it. The meal delivery service probably being cheaper.
The main thing is, with a little work. If you really wanted to I think almost everyone could make their chance of catching this pretty much zero.