Is the word museus the same in Brazilian and European Portuguese?

Yes

The only difference between "museus" in Brazilian Portuguese and Continental Portuguese is pronunciation. In Brazil, the vowels are generally more open and the final syllable is articulated clearly (mu-SE-us). In Portugal, unstressed vowels are much more reduced or "closed," meaning the middle "e" often becomes almost silent or sounds like a very short, neutral "uh," making the word sound much more clipped (mu-Sɐs).

Brazilian Portuguese Examples

1. Os museus de São Paulo são incríveis. (The museums in São __________ are incredible.)
2. Eu adoro ir a museus de arte moderna. (I love going to modern art museums.)
3. Tem muitos museus legais por aqui. (There are many cool museums around here.)
4. A gente visitou todos os museus da cidade. (We visited all the museums in the city.)
5. Quais são os seus museus favoritos? (What are your favorite museums?)

Continental Portuguese Examples

1. Os museus de Lisboa são maravilhosos. (The museums in Lisbon are wonderful.)
2. Gosto muito de passear em museus. (I like walking in museums very much.)
3. Fomos conhecer os museus do Porto. (We went to visit the museums of Porto.)
4. Há museus muito interessantes nesta zona. (There are very interesting museums in this area.)
5. Estivemos a visitar os museus da cidade. (We were visiting the city's museums.)