If you want to know wheather your device is compatible for 5G-use in USA (T-mobile) or not, you have to tell us the exact label or "name" of the phone.
I found, that the Mi10 T-devices (Mi 10T lite, Mi 10T and Mi10T Pro) are compatibel with T-mobile USA 5G-network. You were right with the n41 band.
But Mi 10 lite and Mi 10 Pro (without the T!) doesnt have n41 or n71. It seems, that this devices are not compatible with 5G-T-mobile USA.
5G-Networks are new, they are expanding and for optimal use they need 4G for "playing together". All Xiaomi 10-devices are USA-(and most other countries) 4G-compatible. Because 4G LTE-Networks are often using the frequencies from former 3G bands.
That means, for 5G-compatibility there must be minimum one 5G-band in the "sub 6G-area" - same in the phone and from the network.
n260 and n261 are no "sub-6G-bands", they are "mm-Waves". The frequencies of this bands are in the 26-32 GHz-spectrum. High frequency means short wavelength. mm-Waves have an extreme short range, they couldnt pass a wall or a roof. They can communicate inhouse with things, for example with your coffee-maker. Today, they couldnt be used for typical smartphone-usage. This will come in some (5-10) years. For Xiaomi devices, i couldnt find the mm-Waves-bands (frequence-bands from 6 GHz to 30 or more GHz) in the devices. For the high-band >6 Ghz, LTE-Antennas can be used.
I made a little frequency-band-map for the Xiaomi 10-devices. (sorry i forget the Mi10 Ultra)
Mi10T lite 5G (NSA and SA)
5G: Sub6G: n1/n3/n5/n7/n8/n20/n28/n38/n41/n77/n78
4G: LTE FDD: B1/2/3/4/5/7/8/20/28/32
4G: LTE TDD: B38/40/41
3G: WCDMA: B1/2/4/5/8
2G: GSM: B2/3/5/8
Mi10T (5G: NSA only)
2G: Bands 2/3/5/8
3G: Bands 1/2/4/5/8
4G: Bands 1/2/3/4/5/7/8/20/28/32/38/40/41
5G Bands 1/3/7/8/20/28/38/41/77/78
Mi10T Pro (5G: NSA only)
2G: Bands 2/3/5/8
3G: Bands 1/2/4/5/8
4G: Bands 1/2/3/4/5/7/8/20/28/32/38/40/41
5G: Bands 1/3/7/8/20/28/38/41/77/78
Mi10 lite
2G: GSM:2/3/5/8
3G: WCDMA:1/2/4/5/8
4G: LTE FDD:1/2/3/4/5/7/8/20/28
LTE TDD:38/40/41
5G: n1/n3/n7/n28/n77/n78 (no n41-5G-band !)
Mi10 Pro
2G： GSM：B2/B3/B5/B8
3G： UMTS：B1/B2/B4/B5/B8
4G: FDD-LTE :1/2/3/4/5/7/8/20/28/32
TDD-LTE: 38/40
5G: Sub6G: n1/n3/n7/n28/n77/n78 ( no n41-band !)
(NSA means "no stand alone". It is a compatibility mode together with 4G. SA means "stand alone"; this 5G-mode supports much more functions, has ultra-low-latency, has cloud-native 5G-core, an easy architecture and more.)
