でも何でもない|でもなんでもない

1. 1Rejects a status or label as inapplicable to someone or something.Ex. 1
2. 2Rejects a description of something as having a particular quality.Ex. 2

Used in conversation and casual writing to reject a label or description emphatically, often before giving a plainer characterization such as ただの～ or 普通の～. Unlike でしかない and 〜にすぎない, it denies that something is X rather than saying it is merely X.

• でしかないN2でも何でもない flatly denies that something is A, while でしかない admits it is A but limits it to 'nothing more than A' and can also emphasize positive feelings. The two are not interchangeable, and でしかない works in both speech and writing.
• 〜にすぎないN2〜にすぎない means 'nothing more than A': it admits something is A and only limits its degree, whereas でも何でもない denies being A altogether. 〜にすぎない has a calm tone, is mostly used in writing, and can attach to nouns, verbs, and adjectives, so the two are not interchangeable.
• わけではないN3わけではない politely negates an inference or misunderstanding and can also express partial negation, in a neutral register; nouns and な-adjectives must add な／である before it. でも何でもない is an outright, blunt denial, so the two should not be swapped.
• やしないN1やしない attaches to the ます-form of verbs (する-verbs use しやしない) and strongly denies that someone will do or can do something, while でも何でもない attaches to nouns and な-adjectives to deny identity or nature. Both are colloquial, but their attachments differ, so they cannot be interchanged.
• ものかN2ものか uses a rhetorical question for strong denial; with verbs it can express the will of 'never...' or 'how could...'. でも何でもない denies identity, nature, or state and does not express will, and when denying identity ものか takes な after the noun (noun + な + ものか).

でしかない and 〜にすぎない say something is merely X; でも何でもない emphatically denies that it is X. わけではない negates a proposition without the same emphatic dismissal, やしない emphatically negates a verb, and ものか expresses a forceful rhetorical rejection.