So, what's missing ?
According to Ericsson, violin performance is relatively "objective": most professionals agree on what's bad and what's good, even in a blind test environment. It's the opposite of what general people believe: that music comes down to "individual's taste". It might be true for pop, but not for classical violinists.
I really don't believe coding works like that. If it does, there won't be so many "consider harmful..." memes. You can delibrately practice leetcode, but I doubt if you can delibrately practice coding in the general sense.
In the meantime I opened multiple tabs to skim through and also thought "hmm, small repetitive tasks you practice again and again to perform them perfectly... not applicable to every field then ?".
When they say deliberate practice, they just mean practice. Or practice with focus at most.
Deliberate practice isn't just practicing extra hard. Remember the original research is about violinists.