Desktop Audio Setup with Passive Speakers

Hi all - Looking for help on a desktop audio setup with passive speakers. Much appreciated in advance!

Criteria

• I'd like to be able to use the speakers in a larger living room setup in a future date, but for now they will be used in a small room with my desktop PC. So optimizing for good speakers, but not an amazing amp as I'll look to upgrade that in the future.

• Under $500.

• Will play games, but would like to optimize for high quality music, so bass is not super important.

• Have a motherboard with Realtek® ALC1220-VB, which includes S/PDIF optical out, so would like to avoid a separate DAC if possible

Considering

• Speakers: Q Acoustics 3020i

• Amp: SMSL AD18

Questions

• Will the SMSL AD18 be powerful enough to get good sound out of the 3020i?

• Will not having a separate DAC harm sound quality?

• Looks like a pre-amp won't be necessary. Is that right?

• Lastly, is this worth the effort and money, or should I just go with an active speaker such as R-41PM? Remember, I'd like to be able to use the speakers in a larger room (with a more powerful amp) in the future.