Your homemade ice cream is harder than store-bought, and that is normal rather than a failure. There are two structural reasons, and both are consequences of making real ice cream in a domestic kitchen.
Reason 1: less air
Air makes ice cream compressible, which is what lets a scoop go in. The industry term is overrun, and cheap commercial ice cream can be up to about 100 percent — half the container is air.
A small paddle in a small bowl for twenty minutes cannot whip in anything like that. Your ice cream is therefore denser, and density resists a scoop. This is the same reason premium ice cream is harder than budget ice cream: less air, more food.
Overrun explained covers the concept properly, and it is the single most useful thing to understand about this problem.
Reason 2: no stabilizers
Commercial ice cream contains guar gum, locust bean gum, mono- and diglycerides and similar ingredients whose job is to control water and keep the texture soft and consistent. You do not have them, so your ice cream behaves like the mixture it actually is.
The free fix, for tonight
Take it out of the freezer five to ten minutes before serving. That is it. This is not a workaround, it is how dense frozen desserts are served everywhere — gelato shops hold product several degrees warmer than an ice cream freezer for exactly this reason.
Second free fix: dip the scoop in hot water between scoops, rather than letting the whole container warm up. Warming the tub and refreezing it makes the texture worse next time.
Recipe fix 1: keep the sugar
The most common self-inflicted cause. Sugar lowers the freezing point of water, which keeps part of the mixture liquid at freezer temperature. Less dissolved sugar means more of it freezes solid, which means a brick.
If you reduced the sugar to make it healthier, that is where the hardness came from. There is no way around this with equipment: sugar is doing physical work in the recipe, not just tasting sweet.
Recipe fix 2: add an invert sugar
A tablespoon of corn syrup, glucose syrup or honey per quart. Invert sugars are made of smaller molecules than granulated sugar, so gram for gram they depress the freezing point more effectively, without adding much perceived sweetness.
This is what commercial recipes lean on, and it is the most effective single addition for a scoopable result.
Recipe fix 3: a tablespoon of alcohol
Alcohol does not freeze at domestic freezer temperatures. One tablespoon of vodka per quart — enough to matter, not enough to taste — keeps a lean mixture from setting solid.
Do not overdo it. Too much and the ice cream will not set at all, which is why sorbets and ice creams made with a lot of liqueur stay soupy. This is also why the trick is in the sorbet recipe, where there is no fat to help.
Recipe fix 4: more fat
Fat does not freeze the way water does, so a higher-fat base has less freezable water in it and stays softer. It also holds air more stably during churning, so you get slightly more overrun.
More cream, or a custard base with egg yolks, which adds fat and binds water at the same time — see custard versus Philadelphia.
Two technique fixes
Do not over-harden it. Two to four hours in the freezer after churning is enough for scoopable ice cream. Overnight will give you something noticeably firmer that wants the five-minute rest before serving.
Use a shallow container. A shallow layer is easier to scoop than a deep block, and it refreezes faster after serving, which also protects the texture. More in storing homemade ice cream.
If this is a spin machine
Different problem, different fix. A Ninja CREAMi pint that is too hard usually spins powdery rather than scooping hard, because the machine is planing a very cold, very lean block. The answer there is a splash of milk and the re-spin function, plus a little more fat and sugar in the base.
Creami downsides covers it in detail.
Hard is not the same as icy
Worth separating, because the fixes differ.
Hard means solid and difficult to scoop, but smooth once you get a spoonful. That is this page: sugar, air and serving temperature.
Icy means you can feel individual crystals on your tongue. That is a different failure — see why homemade ice cream is icy.
A batch can be both, and if it is, the causes overlap: too little sugar produces both.