(not) at all; in no way; no matter what
Used with negative verbs to express that something cannot be done no matter what one tries, or that a situation is completely impossible. Often appears as どうにもならない or どうにもできない.
No matter how it's explained, I just can't understand it at all.
There's nothing that can be done about this problem.
I just can't understand his feelings at all.
Emphasizes an extreme degree of a negative state or quality, often with adjectives like 暑い, 寒い, まずい, etc. Conveys a sense of being beyond help or unbearably so.
It's terribly hot today; I can't stand it.
This dish is hopelessly bad.
Today's heat is just unbearably awful.
仕方ない means 'it can't be helped' and describes accepting a situation, while どうにも (especially as どうにもならない) stresses that no action whatsoever can change it.
ひどく means 'terribly, severely' and simply intensifies a negative quality, whereas どうにも in this sense adds a nuance of being beyond help or unbearable.
どうしても looks and sounds similar to どうにも, but どうしても works in both positive and negative sentences ('by all means'), while どうにも is limited to negative or hopeless situations.
如何にも is written identically to どうにも but read いかにも and means 'indeed, just like', so learners must not confuse the two readings and meanings of the same kanji form.
Compound of どう (how) + に (particle) + も (also/even). The combination どうにも literally means 'in whatever way also', which developed into the adverbial sense of 'no matter how' and then into the emphatic negative usage.