Is there a single Linux phone/tablet that can last an 8 hour day of actual use? Librem/Pinephone/Juno can't. My uConsole can't. Different category, but my MNT mini laptop lasts like 4 hours and can't be left in standby for too long or it drains to zero.
Meanwhile, it's been 10+ years since I've worried about daily battery life on mainstream mobile devices, even my 3-5 year old ones. I can fall asleep with Youtube playing and it's still playing when I wake up. I'm certainly not here to dunk on Linux phones. I want one! But if someone willing to put forth above average effort to use these devices can't realistically daily drive them, who can?
What's "actual use"? Furi FLX1 has the best battery life I've seen on a Linux phone. Idling, it last 3+ days. I'm sure it could survive 1 whole day of "actual use". I also think almost any (official) SailfishOS device would last a day of actual use.