For clarity’s sake: On dev you get the usual regular updates via the updater while staying on the same major Android version … until the update support moves on to the next major Android version, which happened on your device (twice since the /e/OS version you are running). As @Manoj pointed out already …
On stable, the developers may additionally prepare upgrades via the updater (“OTA” - over the air) from one major Android version to the next for select devices and select Android version jumps (it’s complicated and takes considerable effort), so this possibility is what you would gain with stable. But there’s no guarantee your device will get any further Android version upgrades offered by the updater after the ones already there or in testing currently.
You can follow proceedings here … https://community.e.foundation/tag/development-updates … section “OS OTA upgrades” in the posts respectively.