Uller
Adventurer
To me the problem is that 8 hours is almost literally nothing. It's the time you spend asleep. Even one full day of rest (two nights) would be massively better.
I have exactly the same problem with the wizard and cleric. It's the time you spend asleep plus a token amount of time while everyone else is cooking breakfast/striking the tent. The wizard and cleric get given their spells just for shirking chores.
That's what you effectively have. You can't have more than one rest in any given24 hour period. So if your party start a rest at 10pm, they can't start another unitl 10 pm the next evening.
In the game I played last night th pcs fought an encounter at 9pm, rested then exploed a ruin starting at 8am. After 4 encounters (and accidentally releasing a vampire into the world) they decided to rest again. But its only 10 am. So they have to safely hole up for 12 hours before they even begin their rest. In that time the villains can take actions to prepare defenses and even start to work against the pcs. Its short enough to keep the game moving and long enough to allow npcs to adjust to the latest actions of the pcs.
In my experience 24 hours is a pretty good time frame for the adventure environment to adjust. When you start talking weeks its effectively a new adventure