Posting here in case other people interested don’t check the Discord. A few hours ago, a patch that adds commands to get and check currently pressed keys in events was added to FEBuilder. Making the RPG walk should work if you use that within a loop in an event.
Initial ASMC made by me with help from Pikmin and Sme, improved and adapted to FEBuilder by 7743.
ASMC that gets the bitfield of currently pressed keys
//GetCurrentlyPressedKeys.s
.thumb
ldr r0,=0x2024CC0 @Key press bitfield pointer
ldrh r1,[r0,#0x4] @Key press bitfield start
mov r2,r1
ldr r0,=0x30004B8 @FE8U MemorySlot0
mov r1,#0x0C @FE8U MemorySlotC
lsl r1,#2
str r2,[r0,r1]
bx lr