It's the same BS in Portugal. One option is ordering one from amazon. I found this one https://www.amazon.com/Mint-Mobile-Starter-Verify-Compatibility/dp/B0786RD524/ref=sr_1_7_sspa?keywords=Prepaid+Cell+Phone+Cards&qid=1646089095&sr=8-7-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFBUllDVUIwUldGOTgmZW5jcnlwdGVkSWQ9QTAzNjkwNjQyU0ExRjVRUUwwNE5EJmVuY3J5cHRlZEFkSWQ9QTA1MTgzNjMzSkhDNFJTTFJGTjk3JndpZGdldE5hbWU9c3BfbXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ== I don't know if it is good or not. In Portugal I found there's Lycamobile which can be bought in places like gas stations and supermarkets. I've never seen it or tried it but I will take a look.
Mint Mobile Starter Trial Kit (7 Days Of Service + SIM)
https://www.amazon.com/Mint-Mobile-Starter-Verify-Compatibility/dp/B0786RD524
https://www.target.com/p/mint-mobile-7-day-trial-kit/-/A-54444205
https://www.bestbuy.com/site/mint-mobile-prepaid-sim-card-starter-kit/6310601.p?skuId=6310601
If you don't have a phone, borrow an old unlocked phone from someone for a day or two to get the GV verification accomplished.
After claiming a GV #, remove the trial # from GV, and cancel and forget about the trial #.
To test, you can order a Mint Mobile sim for 99C on amazon with a 7 day trial and see if it works. I'm using a Moto G4 Play as my 2nd line and it's working fine on Tello GSM but I'm pretty sure they said it would not work originally. I ordered the sim for my G7 Plus which qualified and them put it in the G4 to test it and it worked fine. If they won't send you a sim, you can buy from Amazon for $2 Don't port your number get a new one from them for testing purposes and only port your number when you're satisfied.
Even if you need to buy a new phone, you can still keep that phone and use it as a spare WIFI phone at home with Google Voice or give it to someone that would use it. Great as a flashlight, a calculator and for web surfing at home on your WIFI. I think it would still work to call 911 in an emergency. If you have to buy a phone buy a Factory unlocked you could probably get one on Amazon or EBAY for around $100 Check Amazon warehouse deals, the prices drop almost every day and easy return if it does not work. I saw one for $119 earlier today for a G7 Plus 64GB, Factory Unlocked.
Mint Mobile Starter Kit | Verify Compatibility with Our Talk, Text & Data Plans (3-in-1 GSM SIM Card) https://www.amazon.com/dp/B0786RD524/ref=cm_sw_r_cp_api_i_kzN1EbQVPG606
That sounds like the correct item.
Bestbuy is the only place I've seen it.
Could also buy a cheap Amazon gift card from a B&M. (If credit card is your problem).
Add it to a Amazon account and buy this
Get it shipped to a amazon locker. (If shipping address is a problem)
Mint will refund the 5$ when you activate your account.
Not a direct answer to your question, but I don't know another way, goodluck.