I've been on Visible (one of Verizon's in-house MVNOs) for a couple weeks and it's been good so far. Of course, the value of any phone plan is heavily dependent on which network is strongest in your location, so use https://coveragemap.com/cell-phone-coverage to check, and maybe ask around with your neighbors about their experiences. You can use https://www.bestphoneplans.net/plans to filter plans based on your criteria (price, network, data), though pretty much everything under the sun will offer unlimited talk and text. I would be wary of US Mobile as they've got a reputation for silly conditions on promotions and "unlimited" plans that aren't really unlimited. Certainly worth considering, but just make sure you know what you're getting into with any given plan of theirs.
As for phone, if you're an iOS Andy then of course get a slightly older iPhone, specifics depend on your price range and whether you're comfortable with refurbished or not. For Android I strongly recommend a Google Pixel, despite the obvious concerns with Google--they have super long support windows and robust custom ROM support if that interests you. The 9a can be had for $400 currently, even less if you're trading in your current phone.