You're right, the one I was looking at as the 'unlocked' one is an at&t: https://www.amazon.com/Sonim-Rugged-Phone-Unlocked-Renewed/dp/B08J66ZQ87/ref=sr_1_4?dchild=1&keywords=sonim+xp3&qid=1604973515&s=electronics&sr=1-4

Am I correct in thinking that this would be the most "unlockable" version of this phone? As in, being able to use it with independent companies that piggy back off of the bigger guy's towers.

***Edit***

Here's the 'Sprint' Version: https://www.amazon.com/gp/product/B08D8Q7DZR?pf_rd_r=KJE2AA83XM8QXN0VSBRQ&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee