There are a lot of things that can effect when the eggs actually hatch. A really big one is average incubating temperature. If the incubator runs a little warm, they can pip as much as three days early. If it runs a little cool, they can be as late. Some other things that can effect it are heredity, humidity, size of eggs (large eggs are often slower), how they are stored before you start, and who knows what else. But the big one is average incubating temperature.
The only real problem with opening the incubator during lockdown is that you might shrink wrap a chick by dropping the humidity. There is really not much risk of that unless an egg has pipped. Sometimes they will pip on the bottom where you can't see it, so bear that in mind.
I understand you are worried right now, and I know it is a lot easier for me to say it than for you to experience it, but I don't see anything that screams for you to open it. I'd give it at least a couple of more days. Then I would not candle. If you want to check them, do the float test. This one is where you put eggs in warm water and let them float. After they settle down, if something is alive in there, you will see the egg moving in the water.
Also, are you counting the days right? An egg does not have a full day's worth of development a few seconds after it is put in the incubator. It takes 24 hours for the egg to have a day's worth of development. So Day 1 is 24 hours after you put them in the incubator. An easy way to look at it is that the day of the week you set them is the day of the week they should hatch. If you set them on a Thursday, they should hatch on a Thursday. But that is just when they should hatch. A lot of the time, they don't get it right.