So I really want a bullpup and I've been thinking king about the MDR/Wlvrn whatever they're calling it now. I'm torn between that, the tavor, and keltec RDB.
What should I get?

I love my Steyr AUG, most battle proven bullpup. Before recently the AUG was basically the only decent choice. Now you have a lot of newer options. And I gotta say I've been really impressed with the Tavor 7. The Tavor X95 looks like a decent choice also.

Of the options you list, IWI no contest. How anyone could buy a DT is beyond me.

Tavor x95

I sold my MDRx 308 after 2+ years. My issue was that the reciverscrews loosened themself or broke off which pissed me off for such a price.
Except that, it was my favorit rifle all time(B&T APC 308 beeing a dangerous rival) and would buy another one. The Wlvrn seems to have solved my problem by just machining the trunion inside the reciver. Managable/good recoil, handy and accurate (just dont buy a 20" barrel of any caliber for the mdrx/wlvrn)

The forward eject system was nice but it feels after 2 years kinda pointless.
You dont really need to remove the barrel for cleaning except you want to remove the gaspiston.
With the third barrelscrew the return to zero should now be better (had no big issue before with it)
Light for 308, heavy for 5,56 but its multical which is also kinda pointless as you need to re-zero your optic for the new caliber.

It will prob. never get any adoption for any military or LE in a serious country so that gun will never have that military history.

I dont regrett buying it but i dont regrett selling it. Would prob. not regrett buying it again but then prob. 556 and not 308

Aug or X95

PSA has a good sale on AUGS right now - that's what I'd get.