It's kind of tricky to judge, but I'll do it anyway.
First and foremost, Golf of Lune is in my opinion way too friendly to the strategy Legolas employed during your game. Just sit back and build tons of resource structures behind gates and watch the money roll in when they are eventually upgraded. It's extremely risky to raid your opponent's base in this mod anyway, especially with castles. On such a big 1v1 map, it becomes even more evident. This is why I prefer outposts, but that's just me.
Furthermore, it's easy to say this in hindsight, but you made a couple of mistakes.
Immediately going for Beornings was the first mistake, in my opinion. They are too expensive too rush and should time similarly as light siege. Do players rush siege works? Not really, so there is that. However, I do agree with your trampling immunity argument. Also, as they fullfill that role, it is generally a bad idea to use light siege (Beornings thus) against cavalry, because that is what they are most vulnerable to. Yes, even when Beornings do such high single target damage. It is too risky, I find.
The second mistake was not upgrading your lothlorien pikes sooner with master blades. Upgrading archers against cavalry is normally a bad idea, since well you know...cavalry are the natural counter to archers. What you could have tried was to stun his massive cavalry blob with the mystical stream spell and encircle them with master bladed pikes. That would have been nasty.
The third mistake was not concentrating your efforts on the Mirkwood outpost. Generally, lothlorien pikes will do well against regular cavalry, but once they have fully upgraded Gondor Knights, inspired by Dol Amroth Knights, it becomes a different story as you are aware. Generally, if possible, you should anticipate cavalry spam from Gondor when playing as Elves, and try to get out Palace Guards as soon as possible and upgrade them. They will poop on them.
There were some other mistakes, which I forgot by the time I wrote this. You'd also have the typical minor micro mistakes, but the game is old and it is not the most competitive enviroment friendly game, so it is indeed hard to pull off. Like my micro is impeccable in this game haha (I wish it was.)
To wrap things up, I actually think the most remarkable thing of this replay are the eagles versus catapults. I think it is incredibly clear in this replay that flying units do very little against siege units, which we are anxiously awaiting for the corresponding changes from the team
.
Kind regards.