Question Is there a recommended way to do footstep marks?

I can’t find any decent tutorials on how to add simple footstep marks where the player runs. I’m assuming the best way is a particle system trail, but not quite sure how to create it.

is the some resources out there I’ve missed that could help or someone here?

 

I would use decals. You just have to make sure to fade them out and remove them after a while for performance reasons.

 

like poolable gameobject with decals spawned using animation triggers?

 

Gameobjects: Yes
Poolable: Always a good idea
Animation Triggers: If you mean animation events, then yes. But there might be other ways to do it (e.g. collision callbacks).

The more interesting question is how to render the decals. I think, URP and HDRP have them built in. For BiRP there is the not-so-good Projector component. For BiRP, I'd recommend Decalicious from the asset store.
https://docs.unity3d.com/Manual/visual-effects-decals.html