529 to Roth for yourself as Beneficiary

I know in secue 2.0, we can incrementally roll 15 year old 529s into Roths (35K) beginning 2024. I was initially thinking of this for parents who over funded giving their kid access to Roth money. However, for high income earners, can you open a 529 for yourself as beneficiary and then convert it to Roth in 15 years (35K max)? I know that during conversion years you couldn't do this and backdoor Roth. However, for those with big IRAs, this could be good?

Am I missing something?

Also, separate but similar, feel free to post any other resources/thoughts for thinking about 529s as a legacy plan for future generations. Thank you!!