please always specify your device when seeking for help here
For SMS and telephone data, you could use Fossify Phone and Fossify Messages (F-Droid). They do have an export function. (I personally did not use it, since I do not have a SIM card on my smartphone.)
I have moved to iodéOS from CalyxOS in August 25 - did it with Seedvault. Important learning for me was: Don’t restore your backup when the device asks you for it. Let iodéOS install their standard apps (like F-Droid etc.). After that you can selectively restore Mail apps, calender and so on (apps with personal data). All the other apps you can just do a fresh install from F-Droid/Aurora.
Seedvault can restore your SMS / MMS database by itself. But yes other apps can explicitly export and import them as well (I use SMS Import / Export… it does MMS as well and I have had better luck with group MMS with it than with the builtin Fossify Messages import / export), so it is good to maybe have both but just try the Seedvault restore first as part of restore of all the rest too (?)
I did make the same move in October with almost no efforts on a motorola G42 with SeedVault. The suggestion about selective restore from seedvault is indeed important (I did not make it!).
As an additional security measure, I always do some backup, as far as possible with the system offered by each apk, on SD card.
For me whatsap restore “facility” has never succeeded without gougoul. It’s a pity because Meta stays with my messages and I do not !! That’s another reason to quit whtsapp.
For SMS, I recommend SMS Import/Export of F-Droid. Works fine for me.
Welcome to Iodé then
Sorry for you, but I agree with you. I don’t use WA a lot ; almost only to contact shops/sellers/administrations.
For me, copying the Whatsapp directory in Android/media/ was enough.
I see it a little differently: Personally, I prefer a complete transfer when changing operating systems (iodéGSi to ShiftOS-l, ShiftOS-l to iodéOS) at first stage. Then I have to add the F-Droid third-party repositories specific to that OS afterwards, so what.