Roth IRA that meets HMRC requirements to be exempt from UK IHT

Has anyone found a Roth IRA provider that has set up the account to meet the requirements from HMRC to be exempt from inheritance taxes in the UK? The main requirement is that the Roth IRA provider has discretion over how the death benefits are distributed. In practice they would follow the account owners beneficiary request but they are not legally required it did so. This is the same arrangement that UK SIPPs include in their beneficiary distribution process to be exempt from UK IHT and I’m wondering if there is a US IRA provider that does this as well. Thanks!

I have no idea if Vanguard meet the criteria you specify but my wife and I have each set up our children in our Vanguard accounts as the sole beneficiaries of our Roths when we die. Neither of us need each other’s Roth after the other passes so we decided to pass it straight to the children.