lineageos – Rooting Lineage OS through local update?

I’m considering to root my Fairphone 3 running Android 13 on /e/OS (a close Lineage OS derivative). However, I don’t wish to wipe my data by unlocking the bootloader, so I had the following idea to circumvent it:

Manually download the IMG-e-2.4-t-official-FP3.zip update image from the official download site*.
Extract the boot.img from the IMG-e-2.4-t-official-FP3.zip.
Patch the boot.img with Magisk.
Inside the IMG-e-2.4-t-official-FP3.zip, replace the official boot.img with the Magisk-patched one.
Go to settings ➡️ updater ➡️ “apply local update”, and select the patched IMG-e-2.4-t-official-FP3.zip.

Could anything unintended happen if I just ignored the vbmeta.img that is also present in IMG-e-2.4-t-official-FP3.zip?

(I hesitate to install Magisk via recovery, because it’s not recommend on modern devices. Feel free to correct me if that method is still safe on my device.)

I foresee three possible error scenarios:

Android recognises the IMG-e-2.4-t-official-FP3.zip as “corrupted” and refuses to update.
Android does not refuse to apply the update, but fails to flash the boot partition due to the locked bootloader, possibly bricking the device.
While updating, Android automatically unlocks the bootloader to flash the boot partition, wiping my data without prior notice.

What will happen? Should I just try it?

*Please note that various /e/OS services are currently offline, including the update download site: mastodon.social/@murena/113272432488332874