One possibility, where recovery failed to boot is that the data partition is still “contaminated” by stuff from a previous Android version.
Two things would help rule that out. Factory reset after running MSM tool and running fastboot -w (again wipes data) before or after flashing recovery image.
Are you reluctant to go with Android 13 (T) ?
You are probably aware of all the helpful links off https://wiki.lineageos.org/devices/avicii/. Note that these pages are updated for Lineage 20 (… 13 … T).
Edit the pages today are updated for Lineage 21.