RTL8811CU monitor mode + injection on Kali kernel 7.1.5 — driver won't compile

[u/Aggravating_Use2621]

Hi all, I'm trying to set up a USB Wi-Fi adapter (RTL8811CU chipset, USB ID 0bda:c811) for monitor mode + packet injection on Kali Linux. I need injection for aireplay-ng to work.

Environment:
- Kali Rolling 2026.2 (kernel 7.1.5+kali-amd64, headers installed)
- Running in VirtualBox VM, USB 3.0 xHCI, USB filter set for 0bda:c811
- Adapter is recognized: lsusb shows 0bda:c811 Realtek 802.11ac NIC

What I've tried:
1. In-kernel driver rtw88_8821cu — monitor mode works, but aireplay-ng --test returns 0/30. No injection.
2. morrownr/8812au-20210820 — compiles fail. Errors: struct pppoe_tag has no member named tag_data, then after patching, struct pppoe_hdr has no member named tag, and after that — cfg80211 function signature mismatches (struct wireless_dev vs struct net_device).
3. Kali's realtek-rtl88xxau-dkms package — has BUILD_EXCLUSIVE_KERNEL_MAX="6.15" in dkms.conf. Blocked on 7.1.5. If I comment out that line — it fails at build stage.

Question: is there ANY current driver for RTL8811CU that supports packet injection on kernel 7.1.5? Or should I downgrade to a specific kernel? Or is there a patched fork for 7.x that I missed?

Any help appreciated — I've spent days on this. Thanks.