Hsa basically turns into a retirement account when you're old enough. And I assume Facebook has the minimum required deductible to be called high deductible, and I assume you don't have a fuck ton of health problems
Backdoor ira does not work with 250k (it's not pre-tax). It needs to be after tax so first pre-tax 401k seems better. For HSA you need to plan ahead and pick the right plan. HSA is better than pre-tax (if no match is available)
If you make a decent income (200+k) do all of the following: 1. contribute the maximum to your 401k 2. Contribute 5500 to an IRA and rollover to Roth 3. Contribute to a post tax 401k account (mega backdoor) if your company allows and roll it over to a Roth 401k. 4. Max out your HSA if you have a HDHP.
Max out pre-tax 401k and on top do both Mega and "regular" backdoors. Our 401k has the mega built in - after tax contributions+auto roth conversion+rollover to roth IRA anytime. In addition you should do regular backdoor - 6k into traditional IRA with immidiate rollover into Roth IRA