I would suggest you to use a different set of words in your approach to this matter, the perception of the word boycot is rather negative and often associated with brainless/ignorant masses that complain about something that is most of the time completely unrelated to them.
That said the approach i would take at this situation would be that of consumer rights, as in the end this is nothing but twisted bussiness practices, we paid for something and then that something was changed, that much we cant complain about since we were warned about it, yet we were never told that they would halt the project and that they would take the team and the money and run away but since there are not rigid standars (yet) about what they had to deliver they are not doing something strictly illegal.
But we are still consumers and as comsumers we can talk with eachother, exchange opinions and experiences about the product and suggest OR DISCOURAGE the aquisition of that product, so we are technically not boycoting, we are informing our fellow players about the characteristics of this particular product, its developers, and our gameplay experience in it, and we have several tools at our disposals, like game reviews in Steam, Twitter, Gaming magazines or even facebook.
I in particular follow several gaming youtubers that keep their followers updated in regards of the several game's news and updates and ofc every time i see ATLAS mentioned i love to SHARE my experience and knowledge about this game and its developers to make sure that those consumers are well informed before deciding what game to buy, simply because in dark times like this when moral, decency and reputation have lost their meaning we have too look after eachother.