I was in particular thinking about the very broad strokes. the thirty years war, the seven years war, the Napoleonic wars, the treaties and deals after that.
Yes I know they took part in these wars but they never get more then a passing mention in mainstream accounts, Is it simply a lack of information? Was it the tension between Islam and Christianity?
I'll try to answer your question. Sorry if it doesn't satisfy you
In the 18th century, the Ottomans are still pretty active in diplomacy, sending emissaries around to negotiate treaties and manipulate affars. However, in the 18th Century the Ottomans adopted a more neutral stance in their diplomacy, basically preferring peace or diplomacy over warfare, particularly during the Tulip Era (1740-1768). For example, The Ottomans resisted French urgings to war over Poland in 1733 and again in 1756, declared neutrality in the matter of Russian interference in Poland in March 1764, and the renewal of “eternal” treaties, especially with the Habsburgs like in 1739 and 1745. Though they still concluded a mutual defensive alliance with the Swedish and tried to flirt Prussia into an alliance as a mean to block Russian ambitions. So because of that diplomatic policy, the Ottomans missed most wars in Europe on that era like the War of Austrian Succession and The Seven Years' Wars (the latter which proved disastrous for their military development, as they missed the reforms and drills introduced in that war), which of course making them a non-participant in inter-European diplomacy at the time.
In the 19th century, The Ottomans had generally declined in political importance vis-a-vis Europe, but they're still active in diplomacy from time to time. The Ottoman Empire had not taken part in the post-Napoleonic Vienna conferences and so it was not a member of the Concert of Europe and did not play a role in European politics as such. They did however, entered it in 1856 after the Crimean War and so recognized as an equal standing to other European power, at least on paper. Ottoman diplomats later attended the Berlin conference in 1884, contrary to popular belief not to discuss the division of Ottoman territory or to hand over the fate of part of its population to a European power, but to represent the empire as one of the imperial powers deciding on the rules governing the division of Africa as they attempted to reenter the ranks of expansionist empires by asserting itself as also legally entitled to colonies in Africa well beyond Ottoman Libya. It led to the Ottomans claiming the areas in Libyan desert, Lake Chad Basin, Southern Sudan, and the Sahara. That said, Ottoman claims were less respected by the European powers who later concluded secret agreements allotting Ottoman claims to their own dominions regardless of how artful Ottoman's legal arguments were
Additionally, Ottoman role in 19th century diplomacy and politics are largely underestimated or disregarded by scholarship outside Ottoman studies, which hopefully we'll see more works concerning Ottoman politics and diplomacy in that era
Sources:
"The Ottoman Scramble for Africa" by Mostafa Minawi
"The Ottoman Empire, 1700-1922" by Donald Quartaet
"The Ottoman Absence from the Battlefields of the Seven Years War" by Virginia Aksan