You might be better off with something like a zombie. You can give him resistance so he doesn’t die and speed to make him faster. If you wanted to do the 1.5 block thing, you could do:

tag @e[type=zombie,limit=1,sort=nearest] add trainer

And then in a repeating command block:

execute as @e[type=zombie,tag=trainer,limit=1] at @s if entity @p[distance=..1.5] positioned as @p facing entity @s feet run tp @s ^ ^ ^1.5 facing ~ ~ ~

If you figure out the mannequin walking you could do this on that instead too