というものでもない・というわけではない: the difference
Meaning
There is no guarantee that…, Not necessarily
Past papers
Tested once in past papers
Example
愛があれば結婚できるというものでもない。
It is not necessarily true that you are able to get married if you love each other.
Meaning
It is not that, It doesn't mean that, It is not always the case
Past papers
Example
苦情という訳ではなく、提案です。
It isn't a complaint; it's a suggestion.
How to tell them apart
「というものでもない」: rebuts 'it isn't that simple' on grounds of reason and common sense, with a feel of life experience; softer than 「ではない」.
「というわけではない」: clears up a misunderstanding about a specific fact. 「行きたくないというわけではないが、用事がある」 (It's not that I don't want to go, I just have something on).
If the blank follows 「多ければいい…」 or 「勝てばいい…」, choose 「というものでもない」 first.