A few months ago, I watched the first (and only the first) episode of an anime, and now I can't find it to resume watching. It looked promising, but I stopped after the first episode because I noticed it was not a completed season yet and I dislike starting unfinished stories. I have already looked through the watch history on all streaming services I subscribe to, and my current worry is that whichever service I watched it on dropped it from their lineup already.

Here's what I know/remember:

I'm pretty sure I watched this between 2-4 months ago, but also I have a bad sense of time so this is not a strict parameter

I have subscriptions to Crunchyroll, Netflix, Hulu, Amazon Prime, and Disney

At that time, there were only 7 (I think) episodes out.

The thumbnail icon/cover art had lots of blue and white in the art.

The protagonist was a quiet boy who just graduated/left either high school or maybe junior high school. He has blue hair, and he goes to live with a mysterious male relative, who is waiting for him outside his school on his last day to pick him up and drive him to an estate out in the country.

The protagonist and the relative have supernatural powers over water. The protagonist is just beginning to learn about his watery power, and the relative is experienced enough that he is supposed to help teach/guide the protagonist.

This is in the first episode (I think? I thought I only watched the first episode but there's a chance I watched two) so I don't think this counts as a spoiler: there is a scene where the relative is goofing around, makes a sort of golem but out of water, which then goes on to absorb a bunch of trash out of the local river and cause problems.

The general pacing felt slower like you'd find in a slice of life. Even though there was a scene with some action, it did not seem like the goal of this show to keep you constantly hyped up like action stories would. Like, yes there is supernatural/elemental magic fantasy stuff, but we are being calm about it. Kinda like Mushishi.

What was I watching and where did it go?! (And where is it now?)

Also once we figure that out, I'd enjoy suggestions for similar.