Perversely, because the industry creates this pressure, low-tempo periods that are employer-specific cause anxiety and paranoia. This is even more true right now as large companies continue to announce layoffs.
Is boreout actually a problem unless you're expected to be imprisoned in an office every day and maybe, even worse, expected to look like you're "working" even if there's not much to do? In a remote or hybrid working culture, periods of lightweight work should just be regarded as more leisure time for you. Embrace the opportunity for some self-care!
I agree, though I can see this being hard for many. Even when technically resting, knowing you are technically in working hours is often enough to prevent real leisure.