Need serious suggestions...

You’re posting on a Sonos board, so you’re likely to get Sonos related suggestions. If you’re looking for other options, perhaps there are other boards where you might post.

You say “sound system”, but what does that really mean? Are you just interested in music, or are you interested in including a TV set into the mix?

Simple setups can also be combined, so you can add things over time.

For just music, I’d start with a pair of Sonos Ones. Then add a Subwoofer. Or, if you want to invest a bit more in the initial purchase, a pair of Sonos Fives.

Depending on your TV situation, I’d look at the most cost effective (currently) Beam, which you could then add a pair of surrounds (Sonos Ones) and also a Sub (can’t do double duty with the music one easily).