if Budget constrain, can consider ZLT X28 and Fastmile 3, both can lock band.
If want better get Olax G5018 or Telstra AW1000... all can lock band but there are pro and con...
and if very very budget limited, get VN700+  cheap can lock band, but not very good in speed test (due to CPU is IV500).

maybe u might want to have a look from this shop

https://item.taobao.com/item.htm?id=777049255388



You will find it hard to search for suitable 5G modem router in taobao because many of them are their local telco locked model.

so tips to search is go alibaba.com and search for "5G CPE" or relevant keywords, then save the pictures and use image search function in taobao.