Short version: No. You'll need a Dreamcast for the original experience, or host your own PSO:BB server with the changes implemented. Good luck if you choose the latter.
Long version: Every version of Phantasy Star Online after Dreamcast V2 has various changes that make them significantly different from the Dreamcast and original PC versions. One obvious example is the addition of new episodes over time, with Blue Burst having Episodes I, II, and IV, with those additional episodes having their own items. The other big difference: stat changes compared to V2, mostly for balance purposes. There's probably a lot more differences, but those are the two most noticeable ones, and Blue Burst has much more content and changes in comparison.
Now, there's two significant reasons why Ephinea PSO:BB won't ever have such a change.
Reason 1: The amount of coding that would be required to change every part of PSO:BB to work like the DC versions, EVEN everything that wasn't available in the Dreamcast version, would amount to a huge task that would likely end up being a waste of everyone's time. Especially when you consider that this is SEGA coding we're talking about, which is not easy to work with for making such drastic changes. Honestly, you'd be better off playing the Dreamcast version for the Dreamcast rules rather than waiting for a dedicated PSO:BB private server to make such a drastic change just for you.
Reason 2: Unlike all of the other PSO:BB servers out there, Ephinea is the most "vanilla" out of all of them. Thus, while there might be some changes that makes the experience easier for players (such as QoL additions and, recently, single-player versions of popular multiplayer quests), it ultimately retains the same feeling as the original version, as that's the intended goal. To say the least, making a change of such a scale as changing PSO:BB into practically a hypothetical expansion of the Dreamcast version without any of the balance changes is completely out of the question. If you want to play a Dreamcast PSO without actually having a Dreamcast (you can go with an emulator, but honestly, if you're going to play a PSO game on PC, might as well play Blue Burst), you'll have to make a PSO:BB server with Dreamcast rules yourself.
But again.
SEGA coding.
Have fun with that.