Do international alliances always make the world safer, or can they sometimes lead to more tension?

Nowadays global alliances play a crucial role in geopolitics, global tensions, wars... They can bring both safety and lead to more tensions. I view them as a sort of variable that either brings safety, aid, manpower to countries in need that are in the alliance or brings in more tension by dragging in countries that are affiliated with the alliance when there is tension between countries in the alliance and causing problems in countries that are not originally in the conflict. An example of alliances bringing help and safety to a lot of countries is when NATO was created after WW2. It played a crucial role in keeping peace among the countries in the alliance by scaring other countries to attack its members fearing a third world war. But as of recent times an example of a global alliance leading countries to more tension is USA threatening Greenland and Iran stricking British air base in Cyprus. Both of these examples have NATO involved and its allies. One might argue that global alliences cause more harm than good or the other way arround. However i believe thats wrong becuase it has been proven that global alliances do help a lot but they cn also lead to a lot of tension, thats why i believe they are a sort of variable that changes based on the circumstanse. Alas global alliances are not perfect nor are they terrible they both help and harm countries in its alliance.