GL-X3000 4G internet speed problem

I could never get the speeds I saw on the phone. I am very disappointed. Upload speed is beyond bad. In the same place, I sometimes see almost twice the speed with Z flip 3. I don’t understand it very well. I wonder if it is possible to achieve higher speeds with band locking or something? I see upload speed 60 mbps on the phone, I see 15 max 20 mbps on the router.
GL-X3000


Z flip 3