In my opinion, before suggesting equipment, a lot depends on two things.
1. The sound quality you want.
a. how real and detailed do you want the system (music) to sound?
2. What budget you have for this?
I don't recommend replacing everything at once. When one has an already decent system. upgrading one item at a time in my opinion is the way to go. Because the "upgrade" roller coaster is a long trip is you aren't "there" with the system's sound quality.
If it doesn't sound real and can drive you out of the room, then we are talking substantial funds. But again, one piece at a time to see (hear) the improvement over that piece you are considering replacing.
Aurender music server/streamer/ripper is the way to go if you have a large CD collection. No reason to pay a streaming service to hear music you already have.
There is a huge difference between servers. Some will tell you that digital (one's and zero's) are the same and that is actually not true. Just like cables make a noticeable difference,
So, my advice, is to try to find stores/dealers that will let you take equipment home or purchase with a no questions asked return policy and hear it in your home in your system.
Again, change only one thing at a time and set the listening level with the old piece, listen, then measure the db level of that music, swap the new piece in, adjust the listening level to match the previous level and then listen.
Volume/gain level differences, will falsely convince people that something is better, when actually it is simply a gain/volume difference.
For example on changing pieces. If you like having an integrated amp, then stay with that and listen to other integrated amps, to see (hear) if the differences are substantive enough to warrant an upgrade. The new Mark Levinson integrated are pretty nice. But, so are several others. Are they substantially better than your current one? Only you can make that determination in your home doing an A/B comparison.
Digital upgrades. Find some decent servers to compare with what you have now. Aurender is excellent. There are some others, but $$$$$. Again, bit perfect ripping is what you want. Unless you don't want to rip and want to pay for streaming.
Speakers? Wow what a deep rabbit hole that one is. If you upgrade speakers first, a very good pair will reveal the issues with equipment, and the upgrade path will definitely continue.
If you are okay with your current pair, then if it was me, I would look into the digital source first. A good streamer/ripper and a really good DAC. The newer integrated amps might also include a pretty decent DAC, so you might look into that also.
Anyway, more to come?
enjoy