Fwiw, I got a lot of pushback at Google when I requested to go to 80% or 90% (4 day week or alternating 4/5 day week) for the sake of my mental health. I tried to be firm about that being the best accomodation for my needs and got nowhere except seriously burnt-out months later, put on a PIP, worked my ass off to get off the PIP, and finally quit when I couldn't just suffer through the burnout any longer.
Sorry to hear this. Hope you found somewhere better now. In my experience with 4 day weeks - in the public sector e:g gov't, academia, it really means that. You can chill , do caring responsibilities, whatever on the 5th day. And ironically, as result you are more productive the other 4 days. Whereas the private sector is patchy. In a corporate like Google, its less likely to work. I worked for a large US corp where they allowed compressed hours. Still 4 day week but just tiring long days instead. Where they have systems comparing peoples performance on the same grade against each other (a bit like apples and oranges. ;) ) , doing PIPs etc, someone working less hours may be hurt by getting less work done at times. That's fine, because for 80% of the salary the employer should expect 80% of the work (in practice they probably get 85-90% so its a bargain). However, private employers in particular can be rigid and just see that person as having done less. If there's internal politics and everyone's trying to look better than others, sometimes working 4 days makes you miss a crucial meeting and be out of the loop of what you need to do to impress Manager X by end-of-year. Public sector by contrast, its in the culture, for years plenty of people working part-time including some senior managers, more women in senior positions who previously juggled work and kids and know what its like, and, it just works. The work gets done.
I also have a friend at Google successfully requesting a 60%, but they had to change team to do so. They also experienced pushback for it - I'm sorry it went the wrong way for you.
Sorry to hear you had that experience. I’m sure it’s a YMMV type situation and it’s not guaranteed. The few anecdata points I have show that people have done it successfully. But certainly it’s small numbers.
So take those "policies" with a grain of salt.