whether it’s worth investing in a really good phono preamp or not.
It would of very helpful if you let us know what components you have and which preamps your interested in. A budget would would also be very helpful. Then we can give you better advice specific to your audio chain beyond the general.
Also there are good to bad recordings on both vinyl and digital along with different audio chains, no way to start in the ideal equal.
The general consensus is that vinyl sounds better than digital, so it isn’t just Fremer. Digital takes samples of an analog signal which when translated back to analog is not better than the original signal. You sometimes hear of DACs touted as sounding like analog, never the other way. As always, it depends on the quality of the audio components and their synergy in the audio chain. Like Fremer and many others, I have both analog and digital audio chains.