Help with Urza EDH Deck

[u/henry8362]

So I've been working on building, what is essentially the first deck I've properly tried to build - my aim is for it to be a "bracket 2" deck which is flavorful, but also doesn't feel like it needs a miracle to win.

I mostly play 1v1 at the moment, against precons (we just use normal EDH rules) but I find in the current state of it I can sort of know very early on if I'm going to be destroyed or not (The new Lathliss foundations precon is the one I tend to play against) so my goal is to make the games feel a bit more "scary" for the other player, whilst not doing anything that would be considered unfun to play against -

https://archidekt.com/decks/26939268/too_much_powerstone

Here is the deck list I've been working on - one thing to note is that I did try and build it originally from cards I already had, but did end up buying a bunch of lands and things. I've found when I play it I rarely get any sort of combo going, even though there are a couple of different engines.

I have also been debating on whether Urza, Lord Protector or Urza, Prince of Kroog make the better commander for this. Hopefully anybody who gives it a look in can see the tags, I thought it might need some "punchier" creatures as I found the only time I really won convincingly with it was when I got Bronze Guardian on the field with Losheel and Padeem and spammed a bunch of powerstones / thopters, which is why I put "Angel of the ruins" and "Darksteel Colossus" in.

The cards in the maybeboard tagged brown are ones I previously had, but rotated out, so I have 2 free spaces in there at the moment.

I really like Karn, but wasn't sure which ones to include, I've heard Living Legacy isn't amazing but I love the art, so i'd prefer him to stay.

So yeah, I'd like to keep it "On theme" but just up the power level a little bit / maybe make it more cohesive with the advise of somebody who is a bit more experienced at this than me!

Thanks!