Turkey should not invade foreign countries, then they can talk about peace.

I was obviously being ironic above.

The point is that as long as Turkey is opportunistically involved in every military conflict they believe they can get gains from, they can't be seen as a trusted partner by their neighboring countries.

All countries (also people) do that. If you have power, you put in use. See USA(Iraq), Russia (Crimea), Germany (WW2), Britain (colonies) etc... I do not support war or occupation but countries behave like high school children - bullies are going to bully.

But, you find all those countries that I listed above, “trustworthy”, is that correct?

The problem here is, “trustworthy” does not mean anything in international relations. It is all about having the outcomes you want, one way or another. If peace gets you what you want, its great. If war, then you go to war.

That is why European Union removed the borders, unified the economic area, so that they will be too integrated/extremely hard to decouple to have war again, because treaties or trustworthiness is meaningless in scale of countries.

It's not completely random, e.g. it would be very hard for a politician in USA to convince population that it is a good idea to bully Canada. And it would not require any convincing for Turkish citizens to accept any action against Greece. So being extremely suspicious of Turkey is the only possible policy for Greece.