Seeking 401k advice for after quitting

Need help knowing if this is a valid/legal/not stupid plan.

Im 37, planning to retire at 45. All my money is in retirement instead of brokerage, and 7-8 years isnt enough time to sack away enough in a brokerage to last me 15 years. I will save what I can, but will need to dip into retirement funds. So I have to get creative with my withdrawal plan. Im not willing to work an extra 15 years just to reach penalty-free withdrawal age. But of course i want to minimize penalties where I can. Here’s my plan:

My 401k is part traditional and part Roth.

So when I retire, I’ll roll that over, splitting into two separate traditional IRAs and one Roth IRA.

I already have a separate Roth IRA so then I would have two Roth IRA’s just sitting there with no new contributions. I assume that’s ok.

With the two traditional IRAs, I will set up an SEPP in one of them for the maximum I can set it up for. Even if it’s more than I need. I will bank the rest. Because over those 15 years before 59.5, inflation will hit and I won’t be able to raise the withdrawal. I’ll make up the rest with whatever brokerage I can save before retirement, with Roth contributions withdrawals as the emergency lever.

The other traditional IRA I will use to pay my health insurance premiums while unemployed (withOUT the 10% penalty, because that’s allowed now, right?) and it will be sized only for that during the split.

Is all of this allowed? Not sure Im understanding all the rules.