but is there a more dynamic way to instantly show one of the attributes of the entity, without creating a template sensor ?
When you say ‘show’, do you mean for lovelace only? There is a custom card that will show you attributes at a glance if you don’t want to create a sensor out of it.
But, Burningstone is correct here. The best way is to create a template sensor for the attributes you want to track, and is highly recommended if you plan on doing any sort of triggers based on these attributes.