I missed part two of the question, how it's changed. The mileage hasn't changed much, nor has my pace, but the elapsed time has gotten longer in retirement. I'm more likely to bring a lunch, a lock, extra water and clothing and make a day of it. I'm also more likely to spend more days on the bike, since some other activities are on hold because of this bug that's been going around.
My wife is a geocacher and when I go out with her, it'll take all day to ride 40 miles. We have a picnic lunch and see a lot of fun stuff. We get most of our errands and shopping done on the bikes too. Even at Costco!
Most of our cycling has been touring and commuting, so we're geared up to carry stuff, used to being outside all day, and finding creative places to pee. COVID just reinforced those skills.