I’m looking for something that’s going to maximize the qualities of the speakers@abd1 I’d start by learning how your system sounds with the Tektron EL-84s driving your Nenuphars. That may (will) help inform next steps...
If you have regrets letting your LTA amp go, I suggest bringing in a new unit to test with the Nenuphars, after the Nenuphars have 200+ hours on them. I’m not encouraging you to do so, but LTA has a generous return policy should you need to use it.
Don Sachs’ preamps are very well regarded, therefore going amplifier only (versus an integrated) is certainly an option. An integrated option is totally fine as well.
The Ayon Audio Crossfire PA Stereo amplifier is one of my own top choices to tease out how a higher power output design (30 watts) compares to my 2A3 amps (3.5 watts).
Member @mikeg used the Ayon Odin III amp in his review and is familiar with the Ayon line. I suggest reaching out to him for insight and advice, if Ayon is an option.
I concur with the entirety of Charles’ preceding post. To reinforce one point, lower output amps do not generate much heat. My solid state class A amps have been the worst offenders, when it comes to heat generation.
Final point: consider your system as a whole (panel box forward through to your room)... not just the amplifier - speaker pairing... to inform and guide your choices.
Based on reading through your posts, it’s clear you know what you are doing. Trust yourself.