I like, and own, tube gear. The amp, more than anything, determines the sound. I think one should find the right tube amp first, and then use whatever linestage you have. My preference, again will be tubed, but, the choice isn’t quite as critical as the amp.
So much of the sound of the amp depends on compatibility with choice of speaker, type of amp (single-ended, pushpull, output transformerless), choice of output tube type, and quality of parts (particularly the output transformers). Make good choices here and spend most of the electronics budget here, and the sound would be good with any decent linestage.
Because most tube amp designs don’t really need gain or drive from the linestage anyway, it makes sense to buy a good integrated amp which is often not much more than a tube amp with a volume control, source selector switch and extra input jacks added to a basic smp.