If you're on T-Mobile, you might want to consider Google Fi. According to this data prioritization guide, Google Fi gets the same quality of service as standard-tier T-Mobile plans (lower QCI values are better, and both are on QCI 6):
https://www.reddit.com/r/NoContract/comments/oaophe/data_pri...
> QCI 6 is applied to all of T-Mobile's postpaid and prepaid plans (except for Essentials) and Google Fi which also has QCI 6 as well. This means if you want the absolute best from T-Mobile, you want to get a plan directly from them. Even their cheap $10 prepaid 1GB Connect plan has priority data.
Google Fi also gives you unlimited 5G / LTE data when roaming outside the US as well. For their unlimited plus plan, it looks to be on par with the T-Mobile magenta plan in terms of price.