I’m not a landscaper, but I think you need to stake the tree again and leave it staked until the trunk is strong enough to withstand wind.

The tree is so young that it can no stand up straight. If you stake it, the trunk will always be weak. If Wind is a problem, support it with a ring, that will allow the tree to move and develop its "muscles"

For years I watched the very top leader on my Nuttal oak grow off at an angle to the main tree. I worried that would grow crooked. 10 years later the tree is nice and straight about 8" on the trunk and about 40' tall.

PS: in looking at the picture if your yard is the size of the one across the street, the tree may grow way to large for the available area. The trees will grow to at least 50' high and the canopy nearkt 40' in diameter.

https://www.arborday.org/trees/treeguide/TreeDetail.cfm?ItemID=1092

Did I ruin this tree? :(

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no.. tree time is counted in decades ... and in tree time.. it will be fine ... when its a foot thick.. you will never be able to tell... lol.. presuming you have the patience to wait that long.. lol ...

your only mistake was going for some level of instant gratification ... buying a tree that was too tall.. and too thin for its height ...

next time ... buy a tree about half the height.. save a boatload of money.. and avoid the problem entirely ...

smaller transplant trees .. get over the shock/stress faster.. get established faster.. and usually outgrow the larger transplants in a few years ... and save you lots of money ... which is apparently a big deal to me.. lol ..

and.. just guessing here.. never rely on a builder to pick trees ... maybe he thought he was doing you a favor picking a taller one ...

ken