My experience were the first 2 years I was writing wholly new code and was able to write a ton. The next 3 years was all maintenance for new issues, requirements and I felt unproductive.
Also, just in general it felt like my output went down 50% or more because of code review and tests. Those were all essential but up until my FAANG job no team I was on did that stuff (games). We'd just make the game and file bugs while playing. We didn't write tests. We shipped too. I see the value and essential requirement for code review and tests, specially outside of games, but it was a rude awakening just how much slower things went.
There was also just process. Because of code-review you were required to write small changes which I totally understand the need for but it also felt shitty to have to babysit several changes through the CI. Can't submit #3 until #2 passes, etc... so a it felt like wasting so much time on something that used to be instant on a smaller game team. Another example is review of #2 requiring refactoring #3 and #4. And of course the re-write is correct but having to propagate it through changes was more work than if I could have just submitted one change. Similarly while babysitting this stuff someone would check in something with conflicts and again, fixing those conflicts would have been easier with one large change than 4 small changes so again, just adding what feels like busy work.
I get why it's important, it just feels poopy.