Two summers ago, I had alive langustines in the menu, not lobsters, smaller and with thinner shell. I had to cut them in two, when order was coming(nasty experience!).
Though I love the classic Victorinox(my second chefs knife, I bought it 1 month after my first,and my first became home knife) 25cm chef knife(old style fibrox handle, the new handle designs, fibrox or rosewood I find them looking funny), and this knife can take lots of beating, though it is not flexible, but it is not heavy as well, it was doing the job, but not performing as well. It was breaking the head area, to some smaller cracks most of the time, and not so good at the softer belly area.
Then I tried the identical serated version of Victorinox fibrox 25cm chef knife. Easier to do the job, but still not good enough.
Then I tried the Gekko Hammered finish 24,5cm gyuto, certified 61 Hrc by a papper inside the box(I believe it, it feels hard), a knife like the Kikuichi waricomi Tsuchime(maybe Kikuichi OEM), and it was doing much better than both Victorinox.
I have to say that I don't have a deba(I have to buy one sometime soon).
I consider Victorinox better than all german knives, but they are not the good deal that they used to be, with exception some flexible fillets.
I imagine that a deba will be more helpful.
I also imagine that a Masahiro VC 24cm chef knife will do the job. It is 24+cm, hard hard, wide and no brittle. Think of the deba version of it. Cheaper than the Victorinox you posted