Previously I worked at a very large company, my team was mostly isolated form the rest of the tech stack of that company.
Suddenly came a mandate to try to integrate our systems together, the first goal was to use their authorization system (which involved, I kid you not, setting up 3 separate EKS clusters that talked to each other and if the main one goes down, all go down) that the core Platform team of the company was setting up.
Worse even, the plan was to use us as "guinea" pigs for their new systems before rolling out to the rest of the company because our team was smaller and therefor wouldn't be as impacted by problems on their side.
I was vehemently opposed to this, all our other experiences with their stuff was just a huge amount of pain. I remember clearly a meeting we had where I said: "Why would I use your stuff that is not well documented and that I don't understand when I can use open source stuff that is documented and that I can understand". Their only argument was that said they would have internal support for us.
I came up with this concept that I tried to push on to them, that their stuff shouldn't be this monolithic tower of babel monster, but instead should be a buffet where I can pick and choose what to use. Our requirements were very different from their stuff and I didn't want to run into problems because of stuff that had 0 benefit to us.
I ended up leaving that job mostly because of this.