If you’re super happy with the sound, you definitely shouldn’t be made to feel like you need to upgrade, and I think the folks in this forum will generally have similar sentiments. Are (much) more expensive amps better? In general, yes. But that doesn’t mean it’s “worth it”. That is extremely subjective, and is a very personal decision based on your preferences, how much you notice the changes, and your wallet.
Everyone hits their limit in very different places, and with very few exceptions, there’s always something better that each of us can’t afford, or otherwise chooses to deem as requiring too much more money for the benefit.
To answer your question more directly, I have owned tube and solid state amps across a fairly wide range of price points (though, admittedly, I started at fairly high end for tubes) and have generally noticed and appreciated the upgrades. Keep in mind that tube amps can have very different flavors, even in the same price range.
If you want to explore tube amps in the $1,000-$2,000 range, you can check out offerings from Woo Audio, DNA (Starlett), Ampsandsound, Cayin, Bottlehead, and Feliks Audio, as just a few generally well regarded companies. You can also buy/sell some used amps if you want to explore and get a sense of what’s available without losing too much money for the benefit of trying a bunch of stuff (that’s what I did for a long time before buying my only new tube amp).