I think that you may well be correct that this is likely the blocker.
If I look at husky-ap2a.240905.003-factory-3d55ebeb.zip (Source Factory Images for Nexus and Pixel Devices | Google Play services | Google for Developers) the factory flash-all.sh contains only these “active” lines.
fastboot flash bootloader bootloader-husky-ripcurrent-14.5-12100691.img
fastboot reboot-bootloader
sleep 5
fastboot flash radio radio-husky-g5300i-240308-240517-b-11857457.img
fastboot reboot-bootloader
sleep 5
fastboot -w update image-husky-ap2a.240905.003.zip
However the Full OTA image, husky-ota-ap2a.240905.003-b20862e1.zip (Source Factory Images for Nexus and Pixel Devices | Google Play services | Google for Developers) if extracted by this method [Walkthrough] Extract eRecovery and boot images using payload-dumper-go contains
~/TEST-husky/Extracted_OTA/extracted_20250203_113604$ ls
abl.img bl2.img boot.img gcf.img gsa.img ldfw.img pbl.img pvmfw.img system_ext.img tzsw.img vbmeta_system.img vendor_boot.img vendor.img
bl1.img bl31.img dtbo.img gsa_bl1.img init_boot.img modem.img product.img system_dlkm.img system.img vbmeta.img vbmeta_vendor.img vendor_dlkm.img vendor_kernel_boot.img
Perhaps a download of the Full OTA image would give you the opportunity to reverse the /e/OS changes you already made.
fastboot flash boot <boot>.img
fastboot flash dtbo <dtbo>.img
fastboot flash vendor_kernel_boot <vendor_kernel_boot>.img
Working “in between” Android 14 and Android 15 may carry some risk. I would think carefully whether it is best to go for the downgrade which I have researched, or to use similar to restore and test Android 15.