Well you still can stack the Magical Abilities For example a +3 Shield with the... Spellward? (the legendary anti spell shield). I was looking at this Website since Tree Kreen exist and My Question has been answered. So now you have the Legendary Spell Protection of the One Shield and the AC (+5) of the other.
Not sure what legendary shield you are referring to but the “You can benefit from only one shield at a time.” might interfere with that.
You can only benefit from ONE shield at a time.
"Sooner or later, your Players are going to smash your railroad into a sandbox."
-Vedexent
"real life is a super high CR."
-OboeLauren
"............anybody got any potatoes? We could drop a potato in each hole an' see which ones get viciously mauled by horrible monsters?"
-Ilyara Thundertale
Not sure what legendary shield you are referring to but the “You can benefit from only one shield at a time.” might interfere with that.
EZD6 by DM Scotty
https://www.drivethrurpg.com/en/product/397599/EZD6-Core-Rulebook?