The only way you will know if it works for you, is to obtain a SIM and to test it.
https://www.lazada.co.th/products/no1-my5g-30mbps-25030-12-i4889381291-s21251439863.html
https://www.mybynt.com/en/PrePay.php?package=308_my-5G-แบบเติมเงิน
The Unlimited 10Mbps 12 Month package for 1450 baht mentioned earlier, is actually by NT Mobile, rather than My by NT , but also utilises the 700 MHz band.
NT Mobile(TOT). My by NT(CAT).
The Unlimited 10Mbps package for 1350 baht is from My by NT: https://shopee.co.th/ซิมเทพ-my-by-NT-ซิมเน็ตเกินร้อย-10Mbps-ไม่อั้น-ไม่ลดสปีด-นาน-1-ปี-โทรฟรีทุกค่าย-60-นาที-เดือน-สัญญาณโรมมิ่งทุกคลื่น*-i.330732583.24805705284
Confusing? 😊
So to test NT Mobile beforehand, you would also need to obtain a normal SIM to test before springing for an annual pack.
Alternatively, since you have a Thai partner, you can consider https://gomo.th/package
as it uses the AIS network. You buy a 12 month validity SIM for 99 baht and then apply the Unlimited 10 Mbps pack for 149 baht + VAT monthly
Another thing to consider is whether you actually need Unlimited. How much do you use on average? Would 100GB monthly suffice?