yes, agree with other comments to see a tax accountant / lawyer....but here is something to consider (but may not meet your objectives)
You are correct that ordinary income in the trust can be taxes as high as 37% - and that occurs at just $13,050 of income with really no standard deduction. if the income is distributed, then the beneficiary will pay the tax at their tax rate. The marginal tax rate on $14,000 of income is 37% in the trust, but could be as low as zero for someone whose only source of income is the trust income (received on a K-1) and is over 65 years old, so it's a big difference and a big decision.
The tradeoff of keeping the money away from your sister is that it is taxed within the trust at a much higher rate when it is distibuted out of the IRA and subsequently any income derived on the non-qualified assets.
This is a good article that explains alot - note that under certain circumstances, the IRA has to be distributed in as few as FIVE years. Note the article was written in June, 2020 and some of it may be outdated as there has been alot of movement on the rules regarding the 10 year payouts recently.
https://www.fiduciary-trust.com/insights/naming-trust-ira-beneficiary/
How much momey are we talking about? There are costs to set up the trust and adminsitrative costs to maintain the trust (think investment advice and accounting fees to submit the tax return).
I don't know of a way to name the beneficiary of the IRA as the Trust but at the same time get the indiviudal income tax treatment that an individual who received the distribution directly from the trust would receive. If you figure it out (unlikely), please post it!
