I know this issue is touched a lot on this forum, yet I want to open this discussion with the goal in mind to assemble any ideas, future plans or solutions for the average GrapheneOS enjoyer (like myself) because in the end, we all probably enjoy the project, but we cannot do so for long until we have to charge our phones again :(

TLDR: I don't see why the OS doesn't offer a whole lot battery saving features: Its just the main activities on my phone draining my battery. When in idle, it doesn't lose much battery. I'm suggesting that we need battery saving settings that let us more or less underclock / undervolt or just restrict/reduce the allocated resources to certain applications or in general to the hardware components.

I've went through a couple of popular battery-saving methods:

--> Battery + Data saver (disabled Smooth display)
--> LTE only
--> Roaming Data and Bluetooth only when needed active
--> minimized background processes
--> [...]

Yet to my eyes it doesn't really save a whole lot. In the end, I have to charge my phone every day. I'm so frustrated and tired about it, knowing that I bought a brand new - top of the line - phone with such a bad battery efficiency. I don't really want to quit using GrapheneOS, because the reason I bought a Pixel is this project and me thinking I won't need a new phone for many more years. Well, seeing how bad the battery is I fear that this won't be the case.

I've read most of the forum topics addressing this issue. Many are suggestions attempts that I've already linked under battery-saving methods above.
Others are claiming that this is a hardware issue with the CPU (and the network chip).
Now, I'm no hardware / computer expert, but rather an enthusiast: I don't try to step over my lane, just making suggestions. In my free time, I'm toying with hard-/ software, servers and other devices that I have laying around and I'm just asking myself the following question: If this is a hardware related issue, which is caused by the CPU / network chip's efficieny, then why shall we not have general underclocking / undervolting features/settings implemented into the OS? Yes, this wouldn't really fix the real issue, but wouldn't it reduce "the symptoms of this disease"? Meaning: Yes, the CPU (and network chip) would still be unefficent, but you reduce the resources you allocate them so that they don't have much to "dry out". I know of the risks of underclocking / undervolting: This might make your device unstable, but I'm being genuinely honest here: If this becomes a feature, then there shall also be warnings or helping tools. Aside from that, I could be living with my phone rarely / sometimes crashing for way better battery results (if you do underclocking / undervolting right, you can achieve astonishing results with barely no error occurance). This would also come at the cost at performance. I'm just speaking for myself, when I say that I do not really need that much performance that my phone has to offer. I'm not heavily using my phone, just doing basic things like watching videos for some minutes, playing a game that is about 10 years old, hearing music in the background and sometimes just browsing / searching something in the web and you know why I'm posting? Because all of those things, that weren't really an issue before (I had this phone) are draining my battery through the whole day. Its nothing else draining my battery like hell. Just those four: Videos, a 10 year old game, background music (with sometimes bluetooth) and browsing. I have a messenger and something else running in the background: I've checked the RAM usage as well the battery consumption of both: None of them are nearly as much draining my battery as those 4 activities do. Not even the system apps use nearly as much. Those 4 activities do not require masterclass performance in relation to such an intense battery consumption so I don't get why they're given that much performance after all. Coming back to my suggestion: I'm thinking If there were settings to choose how (much) those applications or in generell the device's resources should be used, I'd definitely make a difference in battery reliabilty, since I only see those 4 main activies as the battery killers. (I've managed to set up my phone like that it wouldn't use a lot when idling) I've seen on alternatives devices such settings adressing battery consumption f.e.: "limit CPU usage to 70%" and I don't see no other reasons than the ones I've already covered above to not implement such features.

Let me know what you think about my suggestion or share your own. I'd be happy to get into discussion with you. Thanks in advance.