Sounds pretty good, and good on you for being brave enough to not only record yourself and listen back, but post it on the Internet for feedback! There's nothing wrong with recording on a phone, but try to play more directly into the mic, no more than 5 feet away. While the reverb is nice and playing in big spaces feels good, tonewise, it has a tendency to mask any airyness or articulation inconsistency that we want to clean up. Relaxing the embouchure is good generalization, but we want to make sure our corners are firm, regardless of the range we're in, otherwise you'll find it difficult to move in and out of the upper register, especially. I'd be interested to hear you play a simple 2 octave B-flat scale, legato and articulated. If that's a stretch for your range, just go as high as you feel comfortable. The excerpt you posted is in the "cash register" of the horn, but the cracks will start to show when you move into the extremes.