New to the forum, so HI!

Back in April, I was surprised by my boyfriend with a lovely Chinese Elm, which I decided to name Burton. I live in NY and even though the buildings are tall, my apartment gets enough natural light during the day (3h-4h direct sunlight; brightness all day long).
Recently, I discovered Burton was suffering from a Spider Mite infestation on its leaves. I went to Home Depot and purchased an Insecticidal Soap (https://thd.co/2tLvcuy) and treated the leaves every 3 days with the spray, for a total of 3 weeks, as it was told to me by Home Depot workers. Luckily, the Spider Mites disappeared from the leaves. Unluckily, they found their new home on the soil of my dear Burton.

As if that wasn't enough trouble, I discovered, two days ago, that there are some extremely tiny white worms on the soil. Upon researching what it could be, my best two guesses is that it is either earthworms or grindal worms - although I don't see either being precisely it.
At this point, I'm not sure what to do. I thought about repotting Burton and making sure I really clean it out before repotting, or perhaps treating it with something a little stronger (although I don't want to harm it further). Has anyone ever been through something like this? Does anyone have any tips on what I can try to do, in order to save it? I've watched several videos on YouTube but am still skeptical as to the approaches taken by the owners, seen no one had to deal with a Chinese Elm nor had the same issue.
Really do hope I can find an answer. (or multiple answers hehe)
Thank you!
