I'll air my experience over the years in buying hifi gear in the hope it helps a bit.
I've always had a good idea as to the type of sound I wanted, based on experience with my Dad's ESL57s and 19670s Quad gear but being more into rock than orchestral work also wanted a more heavy weight sound. The transient response and transparent sound was like nothing else I'd ever heard.
In 1990 bought my first system comprising Meridian 206B CD player, Musical Fidelity A100 amp and EPOS ES14 speaker. It was a pretty decent sound for the price and lasted me some years. I always thought the bass was a bit lacking and wanted more "slam"; it was the kind of sound I wanted, I just wanted it "better".
First I changed the amps, I auditioned the Musical Fidelity X-P100 pre with X-A200s vs an integrated amp with a valve pre-amp section. I forget the manufacturer but there was very little difference between them, I went for the MFs but only by a hair.
Still not satisfied, as the amp change did little, I upgraded the ES14s for their floor standing 3 way ES30s. An improvement but it still didn't scratch my slam itch.
So then I thought a much bigger change is needed, which is when (loaded with an £8k budget) I ended up with the Wadia 861 and 300W Muse monoblocks. The biggest surprise in auditioning these was when I changed from single ended RCA leads to balanced XLR - it was like night and day. This setup did me for quite some while, a big upgrade, but still not really satisfied I knew it was the speakers letting me down, which is how I ended up with the ATC SMC40s.
So I might suggest that if you're bored with your system you first work out what kind of sound you want to end up with, this gives you your target sound. Then work backwards from the speakers to create that sound - audition different speakers to see which engage with you. A decent front end will sound like most other decent front ends, its the speakers that will most change the type of sound and then choose amps to go with the speakers.