だけでなく

Means "not only A, but also B". It presents one item or fact and adds another. The added element is often marked with も, but も is optional.

A neutral, everyday pattern used in both speech and writing to add information, such as abilities, features or qualities. The added element often carries も, as in both examples, but a sentence without も is also complete. Compared with the more formal のみならず, だけでなく suits most everyday situations.

• のみならずN2「のみならず」has the same meaning but sounds stiff and formal; it is written language and rarely used in conversation. A na-adjective must take 「であるのみならず」 (not 「な」), and it can also stand alone at the start of a sentence to mean 'not only that.'
• ばかりでなくN3「ばかりでなく」is basically identical in meaning to 「だけでなく」 and the two are generally interchangeable; the following clause can likewise contain requests or invitations, though the tone is slightly more formal. The 「ばかり」 here should not be understood as 'only.'
• ばかりかN3「ばかりか」 carries a stronger tone with a sense of surprise, like 'not just this, but...'; it leans written and is mostly used to state facts or existing situations, with commands and requests rarely following. When describing facts, the two are often interchangeable.
• はもちろんN3「はもちろん」only attaches to nouns (or noun + case particle), and the first item must be something obvious or expected; 「だけでなく」 can also attach to verbs and adjectives, and its first item need not be obvious. When the first item is a noun and is self-evident, the two are interchangeable.
• 上にN2「上に」also means 'not only... but also,' and the two are often interchangeable when both clauses point in the same direction; however, it requires both clauses to be consistently positive or negative, the sentence-final clause generally cannot be a command, request, or invitation, nouns must take 「の」 or 「である」 before it, and its tone is somewhat formal.
• はおろかN1「はおろか」 first mentions something demanding and emphasizes that even something more basic cannot be done, so it is mostly negative, written-style, and stiff in tone; 「だけでなく」 is simple addition with a neutral register, and positive content cannot be replaced with 「はおろか」.

ばかりでなく is nearly synonymous but slightly more formal, and のみならず is a formal, written equivalent. ばかりか often adds a more surprising or extreme second item, はおろか ("let alone") is used mostly in negative contexts, はもちろん marks the first item as obvious, and 上に stresses piling up facts in the same direction (both good or both bad).