Adding more RAM without making any physical changes has been a widespread scam for decades, and well before Xiaomi was even a company. SoftRAM and SoftRAM95 sold by the bucketload before the FTC found in 1996 that they were bogus pieces of software. Nonetheless, Xiaomi now claims to have added 2 GB of RAM to the Redmi Note 10 Pro 5G with a software update.
According to Gizpie, Xiaomi has added a 'memory expansion' setting within MIUI 12.5, presumably V12.5.5.0.RKPCNXM. Once enabled, Xiaomi claims that the setting will provide the handset with an additional 2 GB of working memory, adding that this memory is drawn from built-in storage. However, Xiaomi does not explain that this is just virtual RAM, also known as a page file in Windows.
The Redmi Note 10 Pro 5G has UFS 3.1 flash storage, but this will not be as fast as its RAM. Hence, one should not expect the Redmi Note 10 Pro 5G to suddenly behave as if it has 2 GB more RAM at its disposal. Ultimately, Xiaomi has not done enough in explaining that people will not receive more RAM by enabling this feature.
Xiaomi has not released the Redmi Note 10 Pro 5G outside of China. There is multiple evidence that it will launch the device globally as the POCO X3 GT, though. The devices should share identical hardware.