Is this a meaningful upgrade?

Even Schiit Audio will tell you it is not a needed purchase. You want to scratch an itch you have and I can only deter you as best as I can but if you wanna get it you would but I'd say rather than spend money on buying new gear you can use it for something else as the current one you have is incredible @mashif 

I'd say you should only spend money once you've heard a difference that's worth that much.

I checked your system, I’ll literally listening to JBL 4312A’s on Sound Anchor stands as I type. 😆 A long time ago , I went from a Schiit Bifrost Uber Analog to a used first generation Schiit Yiggy. 2 months ago I updated to the Gen 5 usb. For me it was worth it. I’m not sure how your newer Bifrost would compare but I would get the Yiggy. If I were you I’d consider upgrading to a better streamer as that would probably yield an equal or better improvement. BTW I’m trying to like these 4312A’s but can’t. I’m gonna try a new crossover and if that doesn’t help , they have to go.