I don't really know about all the details of those metrics but I know one thing: Safari is smooth. Actually it was just perfect in the previous years too for me anyway. It just works and works super-efficient. That's why I use it. The only reason I have Chrome installed is to test my websites with Chrome and use MetaMask.
TBH I never understood why people use Chrome on a Mac unless there is a specific extension or site that doesn't work with Safari.
Also, not using anything from Google is a big plus for me to use Safari (or Firefox for the record) anyway.
You can't do proper adblocking (e.g. uBlock Origin) on Safari. That's why I don't really use it except when on battery and out travelling - and even then I'll often avoid using Safari since ads are so awful. Yes, I've tried the Safari adblockers, they suck. As far as I can tell they do marginally more at best than a DNS block.
Once you can't use uBlock Origin with Chrome due to the proposed Manifest V3, Firefox will be the only real option.
Alternatively, many VPN providers offer ad-blocking services, e.g. Mullvad [2].
Both of them use EasyList [3], and you can enhance it yourself with additional (custom) filters.
[1] https://github.com/AdguardTeam/AdGuardForSafari
[2] https://mullvad.net/en/blog/2021/5/27/how-set-ad-blocking-ou...