I have given the seeming modification of the diagonal language $ \{w_i \mid \text{Every turing machine } M_1 \ldots M_i \text{ rejects } w_i\}$ , yet I can’t prove that it is undecidable.
My thoughts so far:

This language is intuitively undecidable, but it might trick you into thinking that it is, and it is in fact decidable: At last there exists an $ i$ from which $ M_i = M^*$ where $ M^*$ rejects every word $ w$ …

I can’t directly reduce this to the diagonal language

I can’t build a halting problem solving machine on this if I can’t define my enumeration of $ w_i$ and $ M_i$ freely, which I can’t (and is that even right?).
A nice tip would be helpful. Thanks ðŸ™‚