Melee characters are ALREADY supposed to guard around themselves at 360°, by the way. Especially if not already engaged by other enemies (which would make them flanked).
The fact that you can jump and/or slowly walk around them to do a backstab is a faulty implementation of the rules wanted by Larian.
Party control in Baldur's Gate 3 is a complete mess that begs to be addressed. SAY NO TO THE TOILET CHAIN
