So helium is a limited resource. Okay gotcha. So why not take two hydrogen atoms. Take their protons and neutrons. And just fucking start squeezing them together until you get helium?
And I don’t mean in the same way you get H2. Those are still separate from each other.
In addition to everything else mentioned, in your scenario, you would also need to pull 2 neutrons from somewhere. A helium nucleus has 2 protons and 2 neutrons, but each H nucleus (generally) is just 1 proton. The 2 neutrons are critical in holding nuclei together.
That’s why nuclear fusion uses deuterium and tricium, isotopes of hydrogen with respectively one and two neutrons. These are much rarer than regular hydrogen, but can be found in some water molecules known as “heavy water”. They can be separated from the other molecules with a centrifuge since they’re heavier. Two deuterium atoms would produce Helium 4, but that’s not the most efficient fusion, and thus not the one that they plan to use in fusion reactors. Instead, they fuse a deuterium and a tricium, resulting in an Helium 5 atom. Unlike regular helium(4), helium 5 is radioactive, but it’s got a relatively short half-life and will soon expell it’s extra neutron, creating the helium we know and love.