Some of them have certain number of initial data on 5G speed (with additional unlimited data on 2G), while others offer all data on 5G.
Here's rank by price for 1 line (with amount of 5G data offered), temp promos excluded:
The best strategy of picking a plan is figure out which of 4 major networks (ATT, Verizon, T-Mobile, Sprint) has the best coverage in your area (all of the 45 plans use one of these 4 networks) and then choosing among plans that use that provider(s).
Coverage maps from providers are misleading/doesn't provide detailed enough picture and we advise to try all providers by yourself or checking how plans on others' people phones work in those areas where you spend a lot of time every day.
Same chart with network used added: