There is no "best" that applies to everyone.... it depends.
There are only three "cell tower carrier networks".... AT&T, Verizon, and T-Mobile. Foremost (for some areas) is picking one that works "where you use it most". If that ain't broke ... don't "fix it"
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Then pick a company that provides a package that uses THAT one.
AT&T and Verizon have always been iffy during peak times here ... so I use T-Mobile.
Even now & then, I have to manually juggle between 5G (5GUC) and 4G (LTE) just for data access .... all on my phone fwiw.
No one size fits all .... hth.