My Current Phone

Model: Samsung Galaxy XCover Pro (SM-G715F)
Purchase Date: October 2020
Durability has been solid. The main reason I need a phone is that the battery is weakening, and the general performance is showing its age. SOT is only 3-4 hours now.

What I Don’t Want (Pixel)

I don’t want a Pixel 7 (or its variants) — for obvious reasons (age, battery, all the problems it has, etc.).
I don’t want the “Pro” versions, because even though they have better specs, the screen size is too big. If a Pro were 6.3", I’d consider it, but they’re all larger.
I don’t want Pixel 7a / 8a etc. They may be cheaper, but in a lot of ways they seem weaker than my current phone — particularly the glass quality (scratch resistance, durability, etc.), and maybe also the overall build.

What I’m Looking For — Musts & Dealbreakers

Here’s the list I’m using to decide. If a phone doesn’t satisfy most of these, I’ll skip it.

GrapheneOS compatibility
This is the other reason I want a new phone. Security. (Which is a recent hobby of mine)
Battery & Charging
New battery health, improved efficiency, and good performance under real-world usage (mobile data lasts 8 hours / WiFi rest), doesn’t overheat, and features decent fast charging (wireless charging not required).
Size: ~6.2-6.3”
Anything over ~6.4” is awkward. Needs to be pocketable, usable one-handed. My current phone is 6.3”, so around that or slightly smaller feels right.
Durability / Premium Materials
Strong glass (scratch, drop protection), IP rating for water/dust, solid build. If it can take a bit of rough use, that’s a plus.
Good Network & Connectivity
Reliable WiFi/cell performance, WiFi calling works well, no weird disconnect issues like with Pixel modems. The phone will be used in low-signal areas, so it has to handle imperfect conditions.
Performance & Camera
Needs to feel like a true upgrade: newer chip, smoother operation, better camera system (low-light, speed, clarity).
Avoid things that feel like a downgrade
Weaker glass, build, massive screen, lower stability, poor support, etc.

My Xcover Pro covers it all. It’s just getting too old, and if I buy a new phone, I want it to be good.

What I’ve Found

Pixel 8 looks like the best candidate so far. It'sit's my size preference (6.2”), looks like an upgrade in hardware, and is excellent for GrapheneOS and security (which is a recent hobby of mine).
But I’ve also seen reviews that point out problems with the Pixel 8: software bugs, overheating under certain conditions, and some durability concerns.
I found a deal for a Pixel 8 for 699 NZD. Is it worth the issues? I will contact the store selling it to get proof that its OEM Unlockable and has atleast 85% battery health. It’s ex-demo.

What I’m Leaning Toward

I’m leaning toward getting the Pixel 8, given the price I saw. It seems the best balance: correct size, GrapheneOS compatibility, and an upgrade in many respects.
But I want to check: do people who have used the Pixel 8 feel like the listed problems are serious long-term issues? Are they dealbreakers or just minor annoyances? And can GrapheneOS fix most of them?
Also, are there other phones I might be overlooking that hit my criteria (Cool Pixel features, similar GrapheneOS alternatives, ~6.2” size, strong build, etc)? If so, I would love to hear suggestions.

If anyone has used GrapheneOS on a Pixel 8, or has good input from experience, I’d really appreciate knowing what your day-to-day is like (battery, durability, any regrets).

Thanks!