This is written by a company that recently raised a series A[1], so I'm not surprised they're willing to optimize for velocity at all costs. It's not the worst trade-off you can make at that stage, but it's a trade-off only worth making early on. And I would argue trust (or lack thereof) shouldn't be a factor in code reviews.
Most of the value of code reviews comes into play when working on more mature systems that sit on top of a stable foundation. And the benefits of those reviews are significant: they help socialize the codebase (I'm using socialize rather than "understand" because I don't think you can get a complete picture of it by doing them, but you can lay down a mental foundation from them) to the team, they let you share techniques and information on how to best utilize a given tech stack, catch missing test cases, identify faulty assumptions, and help Jr/Associate level engineers to be stronger contributors. I've also seen them used successfully as glorified whiteboards/sketchpads to share and develop ideas between engineers.
To extract this value out of code reviews, there are a three key things that must be done.
First, automate as much dumb bikeshedding as you can: have precommit hooks for code formatting, linting, type checking, dependency validation, test coverage etc. Tools already exist for most languages to do this, so you're not stuck having to write your own. A few dozen lines of YAML eliminates hundreds of hours of worthless debates and churn. Nobody should waste time commenting about this stuff.
Second, avoid "large" PRs. Don't get too caught up in change sizes, but think more about "How many major components will people actually need to review?" Sometimes a 2000-line changeset has 1500 lines you just skim and 500 lines of real stuff you have to pay attention to.
Third, you need to give some context in the PR message. Link out to relevant things, explain what you doing, and even call stuff out you want people to see "Please draw your attention to FooBar in baz.py - I'm a little unsure this handles all situations"
Code reviews often get wedged into SDLCs because someone broke something in prod and people concluded "code reviews would've prevented this!" -- I personally think this is the wrong mentality. You should instead see them as a way to improve the quality of the codebase and your team's skills and knowledge. Rather than trying to "catch" a catastrophic production bug, focus instead on reducing the number of catastrophic bugs that get created in the first place - via better tests, better shared understanding, and sharper skills.
[1] https://techcrunch.com/2021/11/30/developer-productivity-too...