possible? sure. easy? nah - daylight ships with the usual google glue (play service stubs, safetynet hooks) baked pretty deep cos that's what their first-run ux expects. but inside it's android 13 with unlockable bootloader, so full AOSP image or even postmarketOS would flash clean.

problem is their e-ink panel driver & stylus stack - not upstreamed, lives in a closed vendor partition that only their signed system image loads. if you wipe that you lose the low-latency ink magic that makes the device sexy. you'd basically be left with a laggy e-reader running mainline.

a nicer play: keep stock android but neuter the google calls. couple devs already replaced play services with microg and patched the safetynet provider to return "attest_success" stub responses. ink still works, apps think they're blessed. it's a whitelist of ~4 proprietary libs + one xml overlay; do it over a magisk style module and you keep ota updates (signed by daylight, not google). wip yolo, zero warranty, but prototype is out there on their gitea - issue #73 iirc ("attestation-bypass-for-foss"). no public bin yet.

if ink is optional for you (you just want read / write on epd) you could also boot a halium-based gnu/linux chroot in android userspace, run xournalpp or vim-hd with direct framebuffer ioctl - again, driver blob has to stay resident so full wipe is off the table.

tl;dr - keep the vendor blobs, gut the google blobs, or port blobs to new OS. second route is closest to plug-and-play today.