Rejecting promotion offer Mid -> Senior

Been working at FAANG for about 5 years. I finally get the second topmost rating and my manager just suggested me to attempt for promotion (I rejected it without any hesitation lol). However, at mid level (L4 / E4) , salary has been more than enough. I've also saved a lot since I've never sold my stocks and it has been up 3-4x from vesting price. I calculated that even if I became Senior SWE I'll probably only earn about 25000$ USD more annually in net. total comp (due to the absurd tax, I'm not in the US). I have many hobbies that I'd like to and able to pursue outside work, precisely because I'm mid level. Working just 6hrs a day and easily getting above expectations (I might need to do overtime to barely meet Senior level expectations), no need to find the next thing to work on by myself, no need to become TLM, etc. are just a blessing. However, thinking back, one concern would be if they stop giving good ratings because they know I just like to coast (since good ratings have quota), or if they start to cut bonus (again, why give bonus to people who just chill and don't want to grow?). Another concern would be if I got layoff, not becoming senior might be an obstacle to get the same salary in another company... So I start to wonder if this is the right move.... Any thoughts? Edit: Mid is terminal level