Hi,I have an old Metro 2018' Samsung Galaxy J2 4G phone..

which is a good size(5.75"x3")for me;had it for 5 yrs. now.
I have the pay as I go per month now;how's Mint Mobile ?
Metro was bought by T Mobile so I want to switch and get a new android phone.
I don't want a huge phone:I like where it fits inside a pocket easily.
I don't know much about how the new phones work;4G or 5G.
Any advice guys? thanks,Bill