Are you sure that you are not just misinterpreting the upgrade instructions?
For the S10 a mandatory wipe-on-upgrade has last been the case when upgrading from versions _older than LineageOS 21.0_.
During the time where LineageOS 20 was the current version there was no requirement to wipe listed at all, so presumably it didn't exist then.
Ah, that might be it. My current version is 21.
> If your device is running LineageOS version older than 21.0, wipe your data partition (this is usually named “Wipe”, “Format”, or “Factory reset”) .
https://wiki.lineageos.org/devices/beyond0lte/upgrade/
Yes ! Thank you, I can upgrade to 22 without wiping.
Are you sure that you are not just misinterpreting the upgrade instructions?
For the S10 a mandatory wipe-on-upgrade has last been the case when upgrading from versions _older than LineageOS 21.0_.
During the time where LineageOS 20 was the current version there was no requirement to wipe listed at all, so presumably it didn't exist then.