Here is the new kernel and the dkms package.
I installed it on my pi4 and discovered that it can not exist on the same USB 3.0 bridge as my usb SSD. I lost my SSD drive the second the 8152 dongle was plugged in. Seems like I may seen similar happening to you previously in your logs above. My previous test was on the vim3 using the internal eMMc.
I then plugged the 8152 dongle into my usb 2.0 port and it worked:
Summary
[ 9.350416] usbcore: registered new interface driver cdc_ether
[ 9.425567] usb 1-1.3.4: reset high-speed USB device number 4 using xhci_hcd
[ 9.611047] r8152 1-1.3.4:1.0 eth1: v2.14.0 (2020/09/24)
[ 9.611059] r8152 1-1.3.4:1.0 eth1: This product is covered by one or more of the following patents:
US6,570,884, US6,115,776, and US6,327,625.
[ 9.611397] usbcore: registered new interface driver r8152
[ 9.621814] r8152 1-1.3.4:1.0 enp1s0u1u3u4: renamed from eth1
[ 11.292813] IPv6: ADDRCONF(NETDEV_CHANGE): enp1s0u1u3u4: link becomes ready
[ 11.293627] r8152 1-1.3.4:1.0 enp1s0u1u3u4: carrier on
[ 11.329232] bcmgenet fd580000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
[ 11.329273] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
Procedure:
Download the tarball and unpack it
cd 8152
sudo pacman -U linux-rpi4-5.10.17-2-aarch64.pkg.tar.zst linux-rpi4-headers-5.10.17-2-aarch64.pkg.tar.zst
Unplug your 8152 usb dongle and reboot. Once rebooted install the dkms package from the 8152 directory:
sudo pacman -U r8152-dkms-2.14-1-aarch64.pkg.tar.zst
Plug in your 8152 dongle and cross your fingers.