Mint Mobile's unlimited plan is a great value especially with the large amount of high-speed data your get. If you can buy one of the larger six or 12-month packages, there aren't many carriers that come close. It also comes with 5G support on T-Mobile's network.
Verizon is buying Tracfone which operates several prepaid brands including Tracfone, Net 10 Wireless, Walmart Family Mobile, SafeLink, Clearway, Total Wireless, Simple Mobile, Straight Talk, and Pageplus. 13 million of Tracfone's 21 million customers already use the Verizon network and Verizon hopes to bring over the rest.
With both of these carriers offering decent unlimited plans, it mostly comes down to which network will work for you. Boost Mobile offers more data in its plans and with the addition of the T-Mobile network, it makes more sense for most people.