Hello!
My pollyfill:

import { Buffer } from 'buffer'

global.Buffer = Buffer

Packages:
"react-native-fast-pbkdf2": "^0.3.1",
"@ton/core": "^0.61.0",
"@ton/crypto": "^3.3.0",
"@ton/ton": "^15.3.1",
"expo-crypto": "~14.1.5",
"react-native": "0.79.5",
"buffer": "^6.0.3",

When I try to generate a mnemonic, the error "TypeError: Cannot read property 'derive' of null" constantly appears. And in a completely empty, new Expo project, await mnemonicNew() gives out absolutely nothing.