how to improve signal and speed on home internet¿

You have nothing to lose but to try.  I sent my "can" back, a few days later  my brother got one around the corner and he got great numbers.  I re-ordered it.  Meanwhile I watched every video on the net and I called T-Mobile and was transferred to a T-Mobile engineer,  he told me the "can" doesn't like being in a window or direct sunlight, keep it away.  My kitchen has 2 windows and putting it higher was the game changer.  If you have a tall piece of furniture in your living room or dining room give it a try.  It just may be perfect or close.