I think the problem with an age gap of 24 and 42 is simply being in very different life stages. I’m 44. At 42, you are thinking about mortgages and pensions and what travel you’ll do when your dc fly the nest in a few more years, and taking on more senior responsibilities with work, possibly also having ageing parents to look after.
At 24, I didn’t even know what I wanted to do with my life or where I wanted to live (I live in a totally different country now, in fact). I was renting with housemates, partying, backpacking, not even thinking about kids but hoping to have them in maybe 10 years, 4 years away from starting a 6 year postgraduate programme, no health worries, no ageing parents, no financial pressures, etc.
42 year old me definitely would not have wanted to date 24 year old me. And most 48 year olds will not want to start over with babies and a new family when she hits 30 and the clock starts ticking.
That said, Dh and I have an age gap. I was 27 and he was 21 when we started dating (he was still in uni 😂). The difference was I was a fairly free spirited 27 year old, backpacking, still figuring out what I wanted to do in life, no ties to anywhere, and he was an unusually mature 21 year old. We were probably the right maturity level for each other. At 29 when I was like, right, time for marriage and babies next year, he was ready and keen at 23, so we got married the next year and started a family. It’s been 17 years and it’s been very happy, but it’s because we were so well suited to each other and not in such hugely different life stages.