How can I get my wife to start looking at her retirement fund seriously?

We're 26, and I'm not trying to get her to dump all her savings into Tesla or FAANG or anything stupid like that.

She's earning a decent salary, and I calculated that if she started actively allocating her pension fund into an all-market index fund like VOO/VTI or just the S&P, we could be set to retire on £2mil in 40 years, mostly thanks to the compound interest over that time period (she's earning £40k with a 10% pension). That would simply be incredible.

However, if she doesn't bother and leaves the pension as it is, she'll be left with something like £300k due to the (at best) 4% returns she'll accrue in the default allocations (shitloads of bonds included which is laughable at this stage of our lives).

I've tried to impress the importance of going into her account (which she's never done before) but she keeps putting it off.

I know we're young and this might seem silly, but even a difference of 1 year at this point could make a huge difference in 40 years time due to the compound interest.

Anyone else had a situation like this before?

She mentioned speaking to her dad who has a financial advisor about it, but I know that he only has about £250k in his pension as it is so I'm not sure I'd be trusting their word when they'll probably recommend something that'll generate below-average returns. For reference, he earns over £80k per year and is expecting to survive on £20k when he retires in about 10 years.