When it comes to decisions like this, I usually make a list with my options, create some categories (e.g. durability, longevity, performance, …), rate each option for each category and then divide each option’s points by its price to see its value. If they’re fairly similar, I would take the time I’d need to save up for them into account.

In general, I would always want to go for A) upgrading what I already have or B) getting something used for the sake of sustainability.

You could look at some more used ThinkPad options like a T470 or a T480. They can often be found for cheap refurbished on eBay. I would also take a look at online benchmarks to see what fits your requirements. In my experience, that works better than looking at spec sheets.