I've never ridden any electronic groupset, so, I am of no use to you on that--sorry.
That said, I have ridden mechanical Ultegra and 105 extensively. I've only ridden the 9100 version of Dura Ace once and pretty briefly. Amazing. Now, I am not some kind of cycling genius, just a guy who rides a lot. What I would say about these three mechanical groupsets is that, were I riding blind, I don't believe there is any way I could distinguish between the shifting performance of 105 R7000 and the current DA. Perhaps on some psychotic hill and a sudden need for immediate, total stoppage, maybe those Dura Ace brakes are a bit better? Dunno about that, but as far as shifting goes, to me, they are the same. Obviously, DA has some technology the other two lack and is, of course, much lighter.
Not really sure where Shimano is going with this, business-wise. 105 is currently such an insane value, I don't know what their value proposition for customers buying new Ultegra is (mech., that is). I have owned and do currently own some Ultegra. But were I buying a bike with mechanical now, I would almost certainly get the 105 R7000 and put that extra money in wheels/other gear. Another nice power meter. etc. Shimano are going to have to do something to better differentiate the two in the next round of updgrades, or Ultegra will become irrelevant for many buyers, IMO. Just my own personal business take and others' mileage may, of course, vary.
Some people really like SRAM. I have owned it and really liked that unique shifting setup. I have found Shimano to be a bit more reliable, though. It might be also worth considering. Don't know anything about Campagnolo.