It depends. If you want a "good" bike then upgrading makes perfect sense. Reynolds 531 never really built a good bike to begin with. That tube set has been around since the 1930s. Its forgiving of frame building mistakes and poorly aligned and lugged tubes can be bent and forced into shape on the jig.
The good stuff is Reynolds 753, 853, 921, 931, and 953. The problem is most frame builders are hacks and can't work with the good stuff. Most US frame builders couldn't manage to pass certification to build 753 bikes. A Reynolds 753 bike will weigh about 1.5 lbs less than a 531 bike and be incomparably stiffer and have more heavenly ride qualities due to the thin wall steel tubing. Its not the flexy boat anchor 531 that can be bent to correct for frame building sloppiness. You can't even cold set a 753 bike. Its that stiff and strong. Which is why most people have never heard of it. The average "master frame builder" is anything but, and most "steel is real" bike builders use steel for reasons of how easy it is to fabricate with steel and how cheap it is, not because the tubing they use builds the best bikes.
So if all you know is 531, then yes upgrade. Find a grown-up frame builder and learn that the false narrative that 531 is the good stuff is just self-validating hooey. If you can't let yourself discover the performance paradigm of a vintage Klein, a vintage or modern Cannondale, or anything modern carbon, then at least graduate to a performance steel bike with the good Reynolds tube sets. Reynolds 531 was a "good" tube set in 1935, not really since.
Think 753 and up, but be prepared to discover your favorite frame builder may not be capable of building with good steel.
Reynolds Technology