Don’t follow the original guide

➜  ~ cd Downloads 
➜  Downloads fastboot flash vendor_boot vendor_boot.img
Sending 'vendor_boot_a' (65536 KB)                 OKAY [  0.516s]
Writing 'vendor_boot_a'                            OKAY [  0.244s]
Finished. Total time: 0.761s
➜  Downloads fastboot flash dtbo dtbo.img                                 
Sending 'dtbo_a' (16384 KB)                        OKAY [  0.115s]
Writing 'dtbo_a'                                   OKAY [  0.066s]
Finished. Total time: 0.181s
➜  Downloads fastboot flash boot boot.img                                 
Sending 'boot_a' (65536 KB)                        OKAY [  0.508s]
Writing 'boot_a'                                   OKAY [  0.228s]
Finished. Total time: 0.737s
➜  Downloads fastboot reboot recovery
Rebooting into recovery                            OKAY [  0.000s]
Finished. Total time: 0.051s

You need to boot dtbo and boot too.

Thanks to: https://www.reddit.com/r/LineageOS/comments/11y3aur/comment/jdafm2k/?utm_source=share&utm_medium=web2x&context=3