Let's suppose there are at least five armor stands.

/summon armor_stand ~ ~ ~
/summon armor_stand ~ ~ ~
/summon armor_stand ~ ~ ~
/summon armor_stand ~ ~ ~
/summon armor_stand ~ ~ ~

What I want to do is repeat the command to tp the player up 1 block 5 times. So that we can move up a total of five blocks. ()

/execute as @a at @s run tp @s ~ ~1 ~
/execute as @a at @s run tp @s ~ ~1 ~
/execute as @a at @s run tp @s ~ ~1 ~
/execute as @a at @s run tp @s ~ ~1 ~
/execute as @a at @s run tp @s ~ ~1 ~

So I made 5 entities use that command each.

/execute as @e[limit=5] run execute as @a at @s run tp @s ~ ~1 ~

The command was executed five times as intended, but was not properly positioned and eventually moved up only one block. () I think it's probably because "run execute" is omitted automatically.
 
This is inconsistent with the case of the function. If you make a function with a command "execute as @a at @s run tp @s ~ ~1 ~"

# main command
execute as @e[limit=5] run function test:test

# test:test function
execute as @a at @s run tp @s ~ ~1 ~

The command moves the player up five blocks () and that's what I wanted.
 
 
Anyway, the point is, there shouldn't be a difference between the two.

/execute as @e[limit=5] run execute as @a at @s run tp @s ~ ~1 ~

# main command
execute as @e[limit=5] run function test:test

# test:test function
execute as @a at @s run tp @s ~ ~1 ~