Hello! You have some nice, fun melodies in your arrangements! BandLab is definitely limited so it's hard to make good strings, but I like the ideas you have in there. I see you tried to control the strings volumes and such, props to you!
Like Jofes said, make sure to add some variations if the instruments are held out longer! It helps with the listening experience, even if it is in the modern-pop genre. Also, in my opinion, try to work your way out of BandLab if you can, you'll be able to understand and create much more in the future. Still, as a novice, good job on the tracks!
Keep working hard and learning as much as possible, and enjoy the process of creation!