Please watch the video for tutorial. Commands Used:

health: /data get entity @e[type=minecraft:horse,limit=1] Attributes[0].Base
speed: /data get entity @e[type=minecraft:horse,limit=1] Attributes[2].Base
jump height: /data get entity @e[type=minecraft:horse,limit=1] Attributes[6].Base

/scoreboard objectives add HorseHealth dummy
/scoreboard objectives add HorseSpeed dummy
/scoreboard objectives add HorseJump dummy

fill ~-1 ~4 ~-1 ~1 ~4 ~-1 minecraft:air replace

execute store result score @p HorseHealth run data get entity @e[type=minecraft:horse,distance=0..3,limit=1] Attributes[0].Base

execute store result score @p HorseSpeed run data get entity @e[type=minecraft:horse,distance=0..3,limit=1] Attributes[2].Base 100

execute store result score @p HorseJump run data get entity @e[type=minecraft:horse,distance=0..3,limit=1] Attributes[6].Base 100

setblock ~ ~4 ~ minecraft:wall_sign[facing=south]{Text2:"{\"text\":\"Health:\"}",Text3:"{\"score\":{\"name\":\"@p\",\"objective\":\"HorseHealth\"}}"}

setblock ~ ~4 ~ minecraft:wall_sign[facing=south]{Text2:"{\"text\":\"Speed:\"}",Text3:"{\"score\":{\"name\":\"@p\",\"objective\":\"HorseSpeed\"}}"}

setblock ~ ~4 ~ minecraft:wall_sign[facing=south]{Text2:"{\"text\":\"Jump:\"}",Text3:"{\"score\":{\"name\":\"@p\",\"objective\":\"HorseJump\"}}"}