OCLP Sequoia not stable on 17.1 iMacs (late 2015)

I tried running macOS Sequoia 15.7.3 (24G419) on an iMac17,1 (Late 2015 5K) using OpenCore Legacy Patcher (latest). Issue:
The system repeatedly becomes unresponsive after login or when reopening multiple windows/apps. After ~120 seconds it panics with:

```userspace watchdog timeout: no successful checkins from WindowServer
WindowServer initialization not complete (post IOKitWaitQuiet)```

This happens even after:
- Clean reinstall of Sequoia
- Root patches applied (in normal mode and Safe Mode)
- NVRAM + SMC reset
- Re-sealing attempts and kextcache rebuilds

Observations
- Hardware diagnosis did not find issues
- Safe Mode is stable (no Metal acceleration)
- Sequoia consistently hangs in WindowServer / Metal initialization
- Panics point to a GPU userspace deadlock, not disk or APFS issues

Αccording to Gemini & ChatGPT, Sequoia is a helpless case on my machine:
"a specific conflict between the Legacy Metal Graphics patches in OCLP and macOS Sequoia's aggressive deprecation of older GPU drivers."

Are they right? Does anyone know of 17.1 iMacs in normal daily use and stable with Sequoia? The AIs seem to agree that there is no hope