Practically speaking? Amps are mature tech.* Pick one with low distortion, linear response, low output impedance, and enough power that you won't clip it, and voila, your "amp problem" is solved for decades.
That's the reductive Arny Kreuger-ish take. Sorry, Andrew!
I do have some techno curiosity about TLS' preferred Quads. Really clever. No crossover distortion with those, class A output without being toaster ovens, low parts count, wide tolerances for those parts, and longevity in spades. Sure, things like crossover distortion in class AB amps is a long solved problem, and any good amp should last a long time. Still, from an engineering+design perspective, those Quads are very interesting.
* Class AB solid state amps are mature tech. If/when I need another amp, it will most likely be a hypex based one, and probably an unglamorous one since I keep the amps out of sight. Those hypex amps seem to be mature tech as well, and bring SOTA performance on the bench that surpasses everything that has come before.