It's like Whack-A-Mole.
You see the issue clearly. What agent wants to do is discriminatory. What ErnieG says will work, but it's more expensive to cover NHCEs.
Some say they provide an additional PS contribution, over and above what is necessary to pass (a)(4) testing, to cover the insurance premiums needed to provide insured death benefits in the DC plan that equal the relative HCE death benefits in the DB plan. Arguably this could work, but this would be a huge amount of work to initially calculate and then monitor and adjust annually to keep death benefits non-discriminatory. Who is going to do this work and who is going to pay for it?
Once all that work is done and paid for, and once the additional PS contributions are made to pay for the NHCE insurance, what's the point? What is the economic benefit of buying life insurance for HCEs in the DB that makes all of this worthwhile?