Please read https://grapheneos.org/features. It covers most features compared to Android 13.
AllowLongSMS -the possibility to forbid auto transform of long SMS into MMS
Use a messaging app which works the way you want.
AnyWebView - replacement of chrome based webview by firefox based
That's not a thing. Firefox doesn't implement the WebView and would be much less secure even if it was an option.
Boot Manager - explicitly forbid some apps to start at phone boot
Use restricted battery mode. It is not a privacy feature though.
Advanced Charging control - set custom charging limits (for example, no more than 85%) with custom PID (restart charging after reaching 85% only if discharged to XX%).
The charging throttling, etc. is built into the OS. There isn't a way to toggle on a limit at the moment but it will slow charging as it approaches 100% automatically.
F-droid privileges to automatic updates from F-Droid
This is obsolete since Android 12. Apps don't need privileged access to do unattended updates. F-Droid is very outdated and has poor support for modern Android, so among many other deficiencies it doesn't support this. It should be noted that F-Droid has major security issues both in the official client and the official repository. You can use a more modern client with unattended update support and fewer issues though.
Any kind of system-wide ad-blockers?
Yes, use either the Private DNS feature or VPN service feature. VPN service apps can support chaining to a proxy or can be multi-function.
Please read the info on the site.