Supervisor revision etiquette?

How much revision is too much for a Supervisor to make? Based on all the original comments I received from my Supervisor I ended up with an overly thorough research proposal of 75 pages including references. Before I could cut it down, my Supervisor then saved a new version and completely rewrote it. Think 50 comments and 80% red revision in every paragraph. They wrote their own abstract completely. It wasn’t based on them being an expert in the field because they haven’t studied the field I am researching and have little technical knowledge.

Is that normal and should I be grateful? I don’t think it teaches me anything.

Additional context: When I started my PhD I started to organise doing a Systematic review with the library team and I was stopped and told to focus on doing a paper first because I had data I had from industry that would make a good paper. I wrote 70% of it and then a conference came up so I presented it there. My Supervisor told me that I could just submit that for my Research Proposal which was completely inaccurate. I also found out that they had my start date as Jan 2024 for the start of term even though I started in April. Long story short, I had to switch to doing my Research Proposal and had to do a quick lit review which I will need to redo for a Systematic one. My Supervisor then couldn’t register as my primary supervisor even though they have been acting as my only supervisor and so my candidature presentation was pushed another month. It feels all stuffed up and I have been told to do my systematic review as my very last paper. 🤷🏼‍♀️🤷🏼‍♀️