Manuscript: vent

I have been writing this manuscript (research article) for at least 6-8 months now which I feel is long overdue. My PI has been setting deadlines at the end of the month for the last 3 months (aka 31st june, 31st july, 31st aug). Every time I get to 98% completion, he decides to suggest gross changes (like for example, type of article, flow of the paper) or add more data. I have already written at least 12 different drafts (with major changes) for the same. Recently he asked me to do a chunk of work and said he believes it would add much more value to my paper. I argued saying it would be a useless exercise but ended up having to do it. Fast forward one month, today he tells me that we wasted a lot of time on the extra work by being greedy, now it doesn't seem so good. Moreover, now he thinks this paper can clubbed with two other papers being written by my labmates, where 3 of us would be combined first authors (backstory: we have had this discussion and have logically opted for sending individual papers for several valid reasons on two distinct occasions). I was motivated earlier and was eager to get it out hoping it might help me with my PhD applications. Given the present state, I have no expectations from this manuscript since applications for 2025 have already started and this paper is no where near submission. I have absolutely zero motivation to take it to completion. How do I keep my calm about this, while I'm already trying to keep up with the application procedures?