Back in the day - rooting Android phones and installing custom ROMs were such a big part of Android. I remember so well using titanium backup and Greenify and Cyanogenmod and the list goes on.
Is it still necessary to root in 2023 though?
I have been on vanilla Android without root access for the past couple of years and at this point most root features have made it into the vanilla Android OS. What are your thoughts?
Necessary for what? If you want to block ads system-wide, you can use the Private DNS feature. But to fiddle with system partition/install Xposed stuff you definitely need root
What DNS do you recommend?
nextdns, ControlD, Rethink DNS and AdGuard all have free tiers with adblocking capabilities and DoT.
I personally use NextDNS, but there are plenty of great options
Adguard has ad blocking DNS servers. They can be a little slow however. Cloudflare and cleanbrowsing both have anti-malware DNS. Cloudflare being the fastest. There are other options too.
1.1.1.1
No 1.1.1.2 and 1.0.0.2 No reason not to use the secure ones.