I documented (a subset of) my experience in [1]. I don't think any of the Google victories there can be considered to be because of personalization.
[1]: https://www.arnavion.dev/blog/2020-12-05-ddg-vs-google/
[1]: https://www.arnavion.dev/blog/2020-12-05-ddg-vs-google/
Today's example: I searched for
> linux nic bonding "bond-mode"
The second result is https://access.redhat.com/documentation/en-us/red_hat_enterp... which does not include the string "bond-mode" (nor "bond mode").