I think you will hear a consensus that the BHK is a significant step forward. At that point it depends on your budget. Not everyone is concerned about the budget factor but it is a consideration in my world at least. If you can land a BHK pre, by all means do so imho.
I have the DSD jr straight to the M700s. I love detail, but at volume it had had too much if that is possible and I heard it and it affected my enjoyment and experience. After watching Paul’s video on pre/no pre etc. I too wanted to experiment a bit. Also, like you mentioned previously I believe, a BHK 250 amp hopefully is in my future. Both BHKs asap are not.
I went shopping “budget friendly” pre-amps. I was steered away from the GCD/Stellar version (especially compared to the BHK) . Finding a high quality pre which is balanced and checks all my boxes is hard. I found two. A W4S and a Cary Audio. I got to test drive a Cary. I don’t know all the cool audio related adjectives but the Cary (mostly at volume) removed stuff I did not like but kept all the stuff I do. It just sounds better. (Sounds like RonP above knows a bit about Cary)
If you are not sure, most any reputable manufacturer (like PSA etc) will let you try out equipment at no or low cost to you. The BHK pre would be the top shelf solution..... Good luck!