I don't know which version of the iPhone SE you have, there have been several over time. Mine is from 2016 (had to look that up). No update to iOS 18, true.

In your specific case you have to look very carefully in the Android world to avoid an even worse situation. I think there are a few Android models now that promise several years of updates, remains to be seen, though. If this is your beef with Apple, then I doubt you will feel much better with Android.