There needs to be done a deep review of cryptography usage. Even though you're saying you're using scure/bip39 for mnemonics, it is not the case for every other feature.
why is crypto-browserify used? It is a very big module and its parts haven't been maintained for >= 5 years. potentially vulnerable to stuff
why is bignumber.js used? There are native bigints.
ethereumjs-wallet v1.0.2 is outdated, it's using old / bad cryptography
ethers v5 uses outdated, old / bad cryptography
All keyring and sdk modules must also be investigated.
There needs to be done a deep review of cryptography usage. Even though you're saying you're using scure/bip39 for mnemonics, it is not the case for every other feature.
All keyring and sdk modules must also be investigated.