I do the "unplug and spend a couple of hours hacking without a charger" thing all the time with mine, and mine's using the previous-generation battery. Not running Windows seems to help a surprising amount.
When I said "screw it" and installed Windows, seemingly my battery woes went away. I used pretty much the same programs (Firefox and Weechat) on both operating systems and I'm pretty much completely stumped. I thought about asking out to Framework support but I don't know what good that would do.
Another issue I've had is not being able to let the thing sit overnight not on the charger since it drains about 10% an hour with the lid closed in both Windows and Linux, so I'm having to remember to leave it plugged in or know that I'm going to be tethered to the wall in the morning.
Regardless of those negatives, I think Framework as a company has done some pretty tremendous things in the laptop space and I hope they continue to do so in the future.
Now you can borrow an USB-C charger from anyone - I've used my Steam Deck charger to charge my laptop (it didn't really charge it as it just slowed down the battery drain, but still it got me through the day). Even a phone charger is better than anything, the extra 10-20W will give you a slight boost in runtime.
My ZenBook happily did 16 hours or more a few times (it claimed 22 out of the box though I never needed to ask it to while I was monitoring), though it doesn't seem to do as well now (it has seen regular use for about three years). There are other designs on the market with similar claims too.
Most people are looking for something that is just movable when getting a laptop though with power being available most of the time, so double a working day (or more) battery life isn't something that sells big (especially if there is the option to trade it for cost or weight) which is part of why you don't see many laptops even trying.
(gaming marketed laptops and other high-power units are a different kettle of fish, you expect and get less life with that sort of use case even with a huge heavy battery or two)