The Moonlander (and most of the ones being discussed) is fully programmable, so you can move the keys around as you wish.
I have ← ↑ ↓ → in a line on the four lower keys on the right of my ErgoDash. Not having the ⊥ arrangement took a little time to get used to.
I considered some fancy QMK (keyboard firmware) hacking to keep the inverted T, and have the key above ↓ change between Z and ↑ depending on the keypress before, but decided it wouldn't be practical. However, the Z is for Dvorak. A Qwerty layout, where it would be /, might cause less trouble.
I've looked at a few Moonlander setups for the keyboard layout that I use on their site [1][2][3] and to my mind the right half is simply missing one column of keys to get a proper cursor key block.
Even the lying-L option ─┘ would mean missing the right shift key (which of course should probably be on the thumb block) and getting used to something different.
I'm not saying it wouldn't work, but for me being from Germany the keyboard is even more expensive than it is anyway and I'm not sure I'm willing to pay that much for the hope that I can adjust to it.
Those layouts have a lot of layers; I didn't have the patience to learn something that complicated.
This is my ErgoDash layout. I have one less bottom-row key than the Moonlander, so I have combined PgDn/LeftAlt and ←/RightAlt onto single keys. I would uncombine these if I had the extra key, as I occasionally press Alt when I intend to press ←, but am too slow.
I also have Enter/Ctrl as a single key, but it's very rare for this to do the wrong thing.
I mostly learned the layout to reduce stress on my hands due to the more ergonomic placement of each letter.
From all the other layers I only use the cursor keys and L3 for []{}<>() and stuff like that, which are much easier to reach and I use a lot when programming.
No, you can have a normal ⊥ arrows layout on the right half [1]. I do as I use those keys a lot. Or I can use a navigation layer as others have mentioned.
The magic is the double use of modifiers if tapped or held.
Whilst I personally could see a need for another column if you have a Nordic layout like mine, but that would make it not symmetrical and unnecessary for English layouts.
For a querty or qwerz layout that would indeed work, if you moved one symbol key (- for german layout, ? for american).
However in my keyboard loayout there actually is a letter in that place (j) [1]. And while I'm willing to compromise on modifiers, page up/down and the like, I draw a line at the stuff that I spent a lot of effort on learning to touch-type :)
As for using a navigation layer - perfectly happy with that 90% of the time, I already use that today, but for some things I just prefer actual cursor keys.
For example selecting an entire word in an editor, you press shift to select, ctrl to jump a whole word and cursor for the direction to jump in. If you add a modifier to that, you start breaking fingers ..
Ah yes, for that layout with 4 extra keys you would have to compromise. E.g. move the ',' or '.'to be shared with the right shift key so that you can have the arrows keys in normal layout. Or just have the left and right on the base layer and all 4 in another layer.
I have ← ↑ ↓ → in a line on the four lower keys on the right of my ErgoDash. Not having the ⊥ arrangement took a little time to get used to.
I considered some fancy QMK (keyboard firmware) hacking to keep the inverted T, and have the key above ↓ change between Z and ↑ depending on the keypress before, but decided it wouldn't be practical. However, the Z is for Dvorak. A Qwerty layout, where it would be /, might cause less trouble.