First question is: "do you want the phone?", followed by, "can you afford it?".
If both answers are "Yes", then, determine the cheapest way to achieve your objective. It is not difficult, just compare the SIM only price with the Phone and SIM price (for same allowance), over (say) 3 or 4 years (or, however long you plan to keep phone).
We have SIM only contracts with Tesco (who use the O2 network). £9/month each for 3000 minutes, 3000 texts, 12GB Data. I have iPhone X, wife has a Samsung S10. The biggest saving was on the Samsung, because, I was able to get significant discount, the iPhone was more problematic, since prices are more controlled, but, it was still cheaper than taking Network Contract. The other advantage of buying the phone is, it is not locked to a Network, so, you can switch Network providers (or, threaten to) if a better deal presents itself.
The discussion regarding having "the latest" etc is not relevant IMHO, some people would be shocked to spend more than £300 on a bicycle, but, many will happily pay £1000+, we are all different, thankfully.