Your technical definition is correct, but you need to consider the practical implications. When you got excommunicated from the Church, people basically stopped taking you seriously, and no one wanted to associate themselves with you. As a consequence, you had no choice but to move elsewhere, i.e. self-banishment.

Interestingly, Galileo called his years in Padua (Padova) the happiest of his life. Florence was much more directly influenced by the church, whereas Padova was part of the Republic of Venice, which was not under the thumb of the church, despite of course being catholic.

If you ever get to visit Padova, there's a great tour of the university that shows a lectern that he used. To put it bluntly, it's a pile of junk, but the story behind that is pretty interesting: rather than hire actual skilled craftsmen to build it, his students - who were not "blue collar" types -wanted to build it themselves as a sign of devotion.

This is just not true in general. The implications were very dependent on where you lived.

You should look up Paolo Sarpi who was a leading figure in the Venetian Republic who Galileo corresponded with frequently. Pope Paul V tried to have him assassinated at one point. If anything he became a more influential leader in Venice after the assassination attempt.

The freedom to work without the more extreme elements of the church getting in the way that was possible in the Republic of Venice at that time is one of the many reasons the position that Galileo opposed the church is hard to defend. If he opposed the church then why did he return to Florence in 1611 instead of staying in the republic.