Lonestarag I had pretty good luck with backup from CalyxOS to GrapheneOS. But as metioned previously for critical data best to perform manually.
On a side note I just backed up and restored GrapheneOS to GrapheneOS and it performed flawlessly. It even reinstalled side-loaded apps like Waze and Netflix.
Make sure you check which folders Seedvault backs up and add any additional folders manually to be backed up.
One disappointment is I had to reconfigure backup settings. I would have expected settings to be restored which would make this more seamless.