I suggest taking some of your upgrade budget and attend an audio show. AXPONA is coming up but there are shows all over the country now. There is no better way to get an idea of how your system stacks up against what is currently available.
I could easily post the same question you have but I don't need to. I'm running a late '90's vintage system with Krell amp and preamp and Thiel CS6 speakers. When they were new they were solid Class A. I've been to three audio shows (AXPONA, Florida, PNW) and I found out that my system holds its own against most of the six-figure systems I heard. In many cases my setup sounds clearly superior to systems where the cabling and power conditioning cost more than my entire rig.
You will hear lots of speakers and some of them will tickle your fancy (I think the rest of your system is fine). You will see that high end speakers sound REALLY different from each other and what you like may be the opposite of what someone else likes. At the 2018 AXPONA they had a pair of large Wilson speakers in a well appointed room and I thought they sounded like fingernails on a chalkboard. Other people I talked to thought they were the best sound at the show. Once you go through this process you can narrow down the choices and make an informed decision. And besides, it's just plain fun.