I've been kinda in the same boat, I've been thinking about getting new speakers (studio monitors) and possibly a new USB DAC.
For speakers I want something flat like reference studio monitors, without overwhelming bass - I'm not a bass fan.
The current Edifier R2000DB bookshelf speakers I use are okay, but their only flaw is at the lowest bass control knob setting there's still too much bass which forces me to use either a hardware equalizer or an equalizer in MC's DSP Studio to reduce bass further. Not having to do that would be a requirement for a replacement.
Another requirement is a volume control knob - the bookshelf speakers I have right now I primarily control volume via remote as the volume knob is on the back of the right speaker and is out-of-reach and I see the JBL studio monitors linked are also like this. Ideally I'd like the volume control to be on the front of one of the speakers however I assume in cases with monitors that have volume control on the back I could 1) max the volume for both speakers on the back then 2) use a potentiometer like a Schiit SYS to control the volume of both? At least that would be ideal and within arm's reach.
I've been looking at the selection of studio monitors on Amazon. The one that caught my attention a little bit has been the KRK Classic 5" studio monitors but I believe they've been discontinued now. If I got any of their newer studio monitors I'd probably have to get a potentiometer that supports balanced (and ideally also unbalanced) output.
As for the USB DAC, that's a bit different. The USB DAC I currently use, the Topping D50s is actually still pretty good overall. However it has one major flaw that bothers me a great deal and is kinda a dealbreaker... its ASIO driver for PCM isn't exclusive but is exclusive only for DSD output. I like to use ASIO over WASAPI Exclusive because I can listen to music and load up things like YouTube videos without it displaying an error about the audio device being in use that happens when exclusive mode is enabled for WASAPI. With ASIO Exclusive I can be actively listening to music then in another app like a web browser I can start a video without error (no audio of course) then I can stop audio playback and audio in the video automatically kicks in. That doesn't work at all with WASAPI Exclusive.
The best ASIO driver I've ever used was Schiit's. Unfortunately since I have DSD tracks and DSD support in the DAC has become a requirement even though I'd love to just get another Schiit DAC and be happy. Oh well.
I'm more flexible with the studio monitors as there's multiple options, just need to know which have a nice flat output without overpowered bass but has good either on front volume control or works fine with a potentiometer like the Schiit SYS. Ideally unbalanced (RCA jacks) would be nice but balanced is fine too as long as a decent potentiometer is available in the same price range of the SYS (again, ideally does both balanced and unbalanced).
With the USB DAC I'd want one that supports up to 32-bit/768 kHz and DSD up to 512, ideally via both native (with ASIO or Linux kernel support) or DoP. The other requirement would be the ASIO output would need to be exclusive for both PCM and DSD.