Xiaomi, Redmi and POCO - one company, three labels
Redmi is Xiaomi's affordable line, Xiaomi-branded devices sit above it, and POCO is the performance-per-rial line. All three are the same company and run the same software.
In practice: a Redmi A-series phone is the entry point, a Redmi Note is the mid-range, and a Xiaomi-numbered phone is the flagship. The same logic runs through the tablets - Redmi Pad below Xiaomi Pad - and the earbuds.
The reason Xiaomi phones tend to look good on paper for the money is that the company prices hardware aggressively and makes its margin elsewhere. That is a real advantage at the budget end and worth knowing rather than treating as a catch.