If you want a DAW that is similar to Ableton and works on Linux, you should go with Bitwig, which is in some ways better and more modern than Ableton, but has a smaller user base.
Can you not do it without the Push?
Even with a Push, there are a couple of WTF omissions that I would have thought would be easy to add, but I assume every DAW will have a few of those.
Lots of people use it Live, mostly negating your argument that the lack of this specific feature makes Ableton unusable live. Actually, is there an alternative DAW that is used live more than Ableton? I would guess the answer to that is "no".