I specifically selected to opt out of 401K at work in many different mediums. I told HR, on paper I marked I don't want 401K and digitally I selected I don't want 401K, I just looked at my check breakdown and they took 401K out...
Discussion
If they ask why you want to opt out, point to this event as evidence of how enept they are.
Depending on your 401K manger (Vanguard, Fidelity, ect.) you can go on their website and or app and change your contribution percentage. I do not see why you couldn't drop it to zero from there.
Keep in mind that under contract that is ultimately your time you sent.
If you currently have funds in an aggressive fund and want to make an attempt to secure your funds in the event of a downturn in an economy then consider a savings and trust account.
Look, ultimately we can't trust this economy, any 401k, fiat, as far as we can throw them but educate yourself to screw them at their own game.
I'm not quite ready to quit my job, liquidate my 401K and exchange for Bitcoin but in the back of my mind it might have to be the option.
I have reduced my contributions to the least amount but still get my max company contributions. It's like free money.
I now just contribute more to stacking sats!