Tom Kunich wrote:

5, 6, 7 and 8 speed freewheels are readily available since most of the
world is still using them. You can even get 9 speed freewheels.

You can get nice 10-speed freewheels from SunRace, too. They're intended for e-bikes with rear hub motors, because those are some of the only bikes that can benefit from them.

The problem with 8/9/10 speed freewheels is the same as it's always been-- when you overhang an axle that far, you bend and then break it. It's enough of a problem with 7sp freewheels that it's why cassette freehubs were developed.

Freewheels that wide are best reserved for e-bike hub motors or other hubs that have thick sturdy axles. There's no technical reason big-axle freewheel hubs couldn't be the default, but they're not. I have made a few of them out of big-axle BMX hubs (and from scratch), but that's a project for a machinist.

If you want to take a crack at it, you can fit a 3/4" or 19mm diameter round axle inside a standard Shimano pattern freewheel remover tool.