Hi so I'm asking this question for a history essay but am struggling to find historical sources to use or named historians opinions(both are required) I was wondering if any books with these could be commented or even the sources/interpretations themselves. I'm mainly focusing on late 1400s to early 1600s.
I would have a look at John Darwin's After Tamerlane: The Rise and Fall of Global Empires 1400-2000. He's quite good on the comparative strengths of these empires and uses quite a lot of named historical sources along with extensive footnotes. I would mine those footnotes for additional reading.
The basic answer from my reading of him, though I'm not a European historian, is that you would have been hard pressed to find a European state with interests in the Balkans (e.g. Austria, Hungary, Poland-Lithuania, Venice, etc.) that would have viewed the Ottoman empire as anything other than an existential threat. The Ottoman "decline" narrative (which, incidentally, has fallen completely out of favor historiographically in the past century) is not something that would have occurred to or at all altered the perceived threat the Ottomans posed to south-east Europe.
Great choice of a topic! However, I suggest you sharpen your thesis and limit your scope in order to make the research feasible within the constraints of your deadline. There was no one Europe, there still isn't today, so you have to at least consider specific nations of Europe.
Most English-language books on the Ottoman-Habsburg war (let's face it -- the Habsburg did almost all the management of war on the "Europe" side) are organized according to the evolution of Habsburg history.
So as an example, in Peter Wilson's The Heart of Europe you can gleam how serious the Ottoman threat was at various points in the history of the HRE, but there is no overview of the enmity during the long time period you are seeking. But this book gives a lot of detail, for example on how much money and soldiery was raised to face the Ottoman threat during the Turkish Long War. It also speaks of the two sieges of Vienna. You can learn about the impact of the specter of Ottoman aggression on German politics in this book, too, affecting the Reformation, the Italian Wars, etc.
Similarly, in the Mediterranean theater, you can find good information around Lepanto through either Crowley's Empires of the Sea or more detailed through Kostam 's Lepanto, but these are highly specialized to Lepanto itself. For a broader view, you may to look through Tinniswood's Pirates of Barbary, Parker's The Grand Strategy of Philip II or Braudel's The Mediterranean in the age of Philip II. None of which span the long period you are asking about.
Otherwise, switch over to the Ottoman-centric view and follow /u/CptBuck 's recommendation.