All the odd cubes (5x5, 7x7, etc) aren’t really much more difficult than 3x3. You can learn basically one or two extra algorithms to reduce it to effectively a 3x3 (e.g. for a 5x5 consolidate 3x3 centers and 1x3 edges, then solve exactly like a 3x3). And honestly the consolidation steps are pretty easy to figure out without actual algorithms for the most part.

I never really messed with even cubes (4x4, 6x6, etc) but I’d imagine they scale the same.

Easily thousands of times. I learned back in high school, on a forum that went on to be a very fondly remembered element of my teenage years.

It’s really not that hard if you can memorize a few algorithms. I learned a very basic set of general algorithms, like half a dozen. Not very efficient, but easy to learn and I can still solve one in about a minute.

If you want to get into proper speed cubing you can learn dozens, or even hundreds, of increasingly specific algorithms. This, combined with a high quality cube and finger tricks, can get you closer to 10 seconds.

But if you just want to be able to solve one, you can learn in an afternoon.

“Oh hey, I’m no longer legally dependent on my parents, nice.”

Not gonna yuck anyone’s yum, but I’ve tried the tunnel and still prefer the hole.