So first, you're mixing vehicles and investments.
There is no one single ideal combination of vehicles, because it depends on the options and individual situation. E.g., most people do best starting with their 401(k)s, but if yours has crappy funds with 2% fees and no match, you might be better off without it; for most people, a traditional IRA is best, but if you are low-income now and anticipate your income going up, you might want to go Roth. I have extra available in my 401(k) due to profit-sharing but am over the income limits for traditional IRA or a Roth, so I max the 401(k) and do a backdoor Roth every year; I also do my own 401(k) contributions to a Roth for a variety of reasons (not relevant here and probably not the best option for most). If you are self-employed, you may have completely different options available and can sock a lot more away. Etc.
For most people here, the preferred vehicles, in order of preference, would include (1) max out 401(k), (2) max out traditional IRA, and (3) save any extra in non-tax-favored accounts. But different people may have different priorities across the tax-deferred vehicles -- if your 401(k) choices are poor and you don't have enough to max out both the 401(k) and tIRA, then do the 401(k) to the match, then the tIRA, and then put whatever is left towards the 401(k).
But no matter the vehicles available, fund choices should be something like Vanguard Total Stock Market Index (fund or ETF), mixed with whatever bond allocation you prefer (I have none). Absolutely no reason to get complicated here (for the vast majority of people). If you want to be really lazy, just choose a low-fee target date fund to manage your asset allocation for you.