Afaict employers typically underestimate the fair present value of future payments when making these offers. Would you mind helping me understand your calculation?
If the payments are adjusted regularly based on how the underlying investments are doing, it should be fair to expect them to be at least somewhat index linked.
Deferring the payment reduces risk, increases convenience, and may be beneficial from a tax perspective. If you don't want to stay up to date and actively manage this, then you don't really have to, unless this deal will for some reason regularly require your active participation. No doubt receiving pensions will be simpler in the glorious automated future.
The future is uncertain, but I have no doubt your recent employer's future prospects are better than that of pretty much any other pension-offering entity and at least comparable to the prospects of the market.
If it's considered to be a trivial sum in the future, then foregoing the lump sum now should be about as trivial from an investment perspective, even though a windfall like that can obviously be used to do something fun now
With all that said, I'd personally take the money now, unless it'd come with a major tax hit. I'm not entirely sure society will exist in 2050 after the hostile AI revolution and I can put the money to better use today than I expect I will in 2050. Pretty sure you'll put it to better use, too.