It's tough to talk about taxes without having the brackets handy. I wrote about the 2017 rates as they were just announced.
The benefit of the 401(k) is the tax deferral and potential shift in brackets, e.g. I deposited most of my working life at 25%/28% but am retired and withdrawing at 0/10/15%. I worked for a large company, with an index cost currently .02%/yr. In your case, we are looking at the trade-off of using a 401(k) with a fee I consider criminal, 1.23%.
You say "high" current bracket, I'll assume 33%. To be clear to readers, you don't pay 33% on all, or even most, of your income, only the taxable income over $233,350. Your $14,925 costs you $10,000 to deposit this year. Instead of tossing number out, which quickly gets tough to follow here's a spreadsheet -
I start by assuming we will look at the decision 10 years hence. The market return is 8% (less the 1.23%). The tax bracket going in (i.e. your current bracket) is 33%. Then after 10 years, this money is subject to 25% tax. This is the rate I'm expecting, given your current retirement account. Then, we analyze to see the result if invested post tax, the net $10,000, with a return of 7.9% (same as the 8% but a .1% fee), but with the 15% cap gain rate.
You can see that the value of putting the money in while in the 33% bracket, but withdrawing at 25% is not negated completely by the fee. Not even after 15 years. Surprisingly, even depositing at 28%/ withdrawing at 25% is worth it if you pull the money out after 10 years. At 15 years, that scenario fails slightly.
In my answer I only address the choices of using the 401(k) vs a post tax account. And my answer, essentially, "It depends" is a function of (a) time, (b) return, and (c) bracket in/ bracket out. You can use a spreadsheet to enter your own assumptions.
If you have no pre-tax IRA money right now, by all means, do the back-door Roth, while this loophole remains open.
Last - if the sheet I posted here isn't clear, comment, and I'll update for clarity.