Ignoring the extremely violent shaking that suggests that a beam struggle was going on when the cutscene happened (given that he sure as hell wasnt physically pushing the lion king back with his arms that were turning to dust) you forget the part where Bedi says Switch on, Airgetlam! It's time for you to tear the light of judgement to pieces! and as we know, that's also when Excalibur's true form was also revealed. And NP Chant? It isnt an NP in the first place, it's the real excalibur. And he clashed with it prior to giving the sword back and was already feeling ill effects. And we know it wasnt Algeltem in that scene or even the previous because it was made clear he took off the cloaking magecraft and everyone wsa like oh shit, it's excalibur. (Also he did reveal it's true name in the prior cutscene, he says it's excalibur).
I should also point out that returning the sword to lancetoria is continuosly being said like that's all that happened, it wasnt, he didnt just simply walk up and hand it to her, there was an exchange going and he overpowered her in that exchange and him alone given the absence of any other character in that entire conversation, given the shaking (which iirc is used when fgo wants to convey beams and the like in cutscnes) was likely a beam struggle. Also nobody said Bedi destroyed the lance and nobody said that giving the sword wasnt what killed him, only the other things happened prior to giving the sword and, well nobody said the first thing at all, we were talking about Ozy destroying the barrier, which is the lance itself.
Regardless, in the final and semi-final cutscene Bedivere, using Excalibur overpowers Rhon, we know it's excalibur because it was established that he took off the cloaking magic that merlin put on it and himself and that he himself says that he's now usng excalibur, and it's outright stated that he destroys a shot from Rhon while simutaneously revealing it's true nature as the sword. Obviously his art isnt going to change or anything, but he is using excalibur in those scenes and at the very least, he stopped a shot from Rhon uing excaliburs light, which as we know, is the giant ass beam that it shoots out given that's how the beam is usually referred to as in text works.