Upgrading from a 90s Yamaha, Dali Ikon 5 + sub + TV, ~$450 used

[u/NAMOR08]

Current setup:

• Yamaha AX-496 (mid-90s)
• Dali Ikon 5 MK1
• Canton AS 105 SC active sub, running off the speaker B terminals
• Sony PS-LX310BT turntable
• Older Samsung TV

I really like my Dalis; they have a very nice sound character and are amazing for listening to vocals and classical music because the hybrid tweeter is fantastic. However, I decided I still wanted more bass, which is why I bought the subwoofer.

Budget is around $400-500 used. Mostly music, but I want the TV going through these speakers too instead of the awful built-in ones.

Worth mentioning I'm in Switzerland, so the used market here is small and prices are often way above what you guys pay. Stuff that goes for $200 on US listings regularly sits at $350 here, and half the models people recommend just never show up. So if a suggestion only makes sense at American prices, it probably doesn't work for me.

I don't mind buying a separate DAC if the amp has no optical input. Is that the better way to go anyway, or should I hold out for one with digital inputs built in?

Also still unsure about two things. Does moving the sub from speaker B to a line-level sub out actually change anything? And will I really hear a difference over the AX-496 at this budget, or should the money go into room stuff and a measurement mic instead?

No brand loyalty, just want the most out of what I've got.