execute positioned ~ ~-1.55 ~ run data modify entity @s Rotation set from entity @n[tag=ballista_stand] Rotation
execute positioned ~ ~-1.55 ~ at @n[tag=ballista_stand] run tp @s ~ ~1.55 ~
execute positioned ~ ~.15 ~ run data modify entity @n[tag=balarrow] Rotation set from entity @s Rotation
execute positioned ~ ~.15 ~ at @s as @n[tag=balarrow] run tp @s ~ ~.15 ~ ~ ~