Qual a diferença entre Mindset e Mentality?

Most of the time they are synonyms and interchangeable.
Then sometimes they aren´t, at times mindset would be meaning " the attitude, opinion or behavior" habitual of someone.
So, it´s more flexible as well. You could change your mindset (by substituting it by another mindset). It is like you have a focus on some behavior, opinion or attitude, etc.

Mentality would be a 'fixed' way of thinking, sometimes 'inherited' from one´s parents or previous generations, or from a given region, country, group, or of a given time (contemporary mentality - for instance) etc.

So, when there´s that difference 'mentality' would be about (inherited) 'beliefs/convictions" whereas with mindset it would be more about focus, tendency, often personal or from a smaller group.

Both are also translated as "way of thinking" but, again I would think the former is a way of thinking more flexible, focus-related and ephemeral in kind that the latter. Of course, you can think of a company (corporate) mindset in terms of 10, 15 years (since a company (life) can be 'long in the tooth'. Even so, it couldn´t be compared to the age of a city (for inllustration´s sake here).