An Interactive Brokers account is opened in your name, which you have direct login access to (although trading rights are still held by Round). Any assets are also held in your name.
With WealthKernel, the account is in your name but assets are held by Wealthkernel Nominees in your name. Wealthkernel is an FCA regulated broker/custodian who follows CASS rules regarding safeguarding of clients funds, assets and segregation from Wealthkernel’s own funds.