I've got a framework 13. It's not better than a Macbook except in terms of user-serviceability.
That said, I do really like the laptop. I just find myself reaching for my macbook especially due to the issue with battery life.
No, it doesn't make sense that a system in sandby would need ventilation. The power draw is very low (not enough to need cooling).
The issue isn't that it's heating up in standby, the issue is that the system wakes from sleep for no reason within the bag.
This did happen to a lesser extent with the older, slower sleep method (S3 sleep), but recent Intel chips and UEFI firmwares have disabled this.
I'd say $400 (minus whatever subsidies from your carrier) is the minimum I'd spend on a smartphone. Could also get an iPhone 12 or something for a bit more.
Point is, iPhones are more affordable than people claim they are, especially in the US. Can't speak for other places where they might be marked up or have high import tax.