DVR especially slow when rendering: what can I do?

As a AMD Radeon VII user under Linux Mint 21.3, I'm sorry to report, like many others did for years, an extreme slowness of my DVR 18.6.6 rendering: e.g. one hour single track HD video rendered in 20 (yes twenty) hours, without re-encoding, only fisheye lens distortion correction!
After roaming around, it seems that OpenCL is slow in DVR and that the GPU should be reverted to CUDA in preferences. But sadly CUDA doesn't show up in DVR preferences pop-up list (screen copy does show it but trust me only OpenCL available). More generally it is not clear if AMD issued a driver including CUDA support which is basically a nVidia creation. Nor if ZLUDA could be used (and how) instead.

My config:
System:
Kernel: 5.15.0-105-generic x86_64 bits: 64 compiler: gcc v: 11.4.0 Desktop: Cinnamon 6.0.4
tk: GTK 3.24.33 wm: muffin vt: 7 dm: LightDM 1.30.0 Distro: Linux Mint 21.3 Virginia
base: Ubuntu 22.04 jammy
Machine:
Type: Desktop System: Gigabyte product: Z390 DESIGNARE v: N/A serial: <superuser required>
Mobo: Gigabyte model: Z390 DESIGNARE-CF serial: <superuser required> UEFI: American Megatrends
v: F9 date: 11/05/2021
CPU:
Info: 8-core model: Intel Core i9-9900KF bits: 64 type: MT MCP smt: enabled arch: Coffee Lake
rev: D cache: L1: 512 KiB L2: 2 MiB L3: 16 MiB
Speed (MHz): avg: 800 min/max: 800/5000 cores: 1: 800 2: 800 3: 800 4: 800 5: 800 6: 800
7: 800 8: 800 9: 800 10: 800 11: 800 12: 800 13: 800 14: 800 15: 800 16: 800 bogomips: 115200
Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
Graphics:
Device-1: AMD Vega 20 [Radeon VII] driver: amdgpu v: 6.3.6 pcie: speed: 8 GT/s lanes: 16 ports:
active: DP-1 empty: DP-2,DP-3,HDMI-A-1 bus-ID: 03:00.0 chip-ID: 1002:66af class-ID: 0300
Display: x11 server: X.Org v: 1.21.1.4 driver: X: loaded: amdgpu,ati
unloaded: fbdev,modesetting,radeon,vesa gpu: amdgpu display-ID: :0 screens: 1
Screen-1: 0 s-res: 3840x2160 s-dpi: 96 s-size: 1016x571mm (40.0x22.5") s-diag: 1165mm (45.9")
Monitor-1: DisplayPort-0 mapped: DP-1 model: Dell U3219Q serial: <filter> res: 3840x2160
hz: 60 dpi: 140 size: 697x392mm (27.4x15.4") diag: 800mm (31.5") modes: max: 3840x2160
min: 720x400
OpenGL: renderer: AMD Radeon VII (vega20 LLVM 17.0.4 DRM 3.56 5.15.0-105-generic)
v: 4.6 Mesa 23.3.0-devel direct render: Yes
Audio:
Device-1: Intel Cannon Lake PCH cAVS vendor: Gigabyte driver: snd_hda_intel v: kernel
bus-ID: 00:1f.3 chip-ID: 8086:a348 class-ID: 0403
Device-2: AMD Vega 20 HDMI Audio [Radeon VII] driver: snd_hda_intel v: kernel pcie:
speed: 8 GT/s lanes: 16 bus-ID: 03:00.1 chip-ID: 1002:ab20 class-ID: 0403
Sound Server-1: ALSA v: k5.15.0-105-generic running: yes
Sound Server-2: PulseAudio v: 15.99.1 running: yes
Sound Server-3: PipeWire v: 0.3.48 running: yes
Network:
Device-1: Intel Cannon Lake PCH CNVi WiFi driver: iwlwifi v: kernel bus-ID: 00:14.3
chip-ID: 8086:a370 class-ID: 0280
IF: wlo1 state: down mac: <filter>
Device-2: Intel Ethernet I219-V vendor: Gigabyte driver: e1000e v: kernel port: N/A
bus-ID: 00:1f.6 chip-ID: 8086:15bc class-ID: 0200
IF: eno2 state: up speed: 1000 Mbps duplex: full mac: <filter>
Device-3: Intel I211 Gigabit Network vendor: Gigabyte driver: igb v: kernel pcie:
speed: 2.5 GT/s lanes: 1 port: 3000 bus-ID: 09:00.0 chip-ID: 8086:1539 class-ID: 0200
IF: enp9s0 state: down mac: <filter>
Bluetooth:
Device-1: Intel Bluetooth 9460/9560 Jefferson Peak (JfP) type: USB driver: btusb v: 0.8
bus-ID: 1-14:5 chip-ID: 8087:0aaa class-ID: e001
Report: hciconfig ID: hci0 rfk-id: 0 state: down bt-service: enabled,running rfk-block:
hardware: no software: yes address: <filter>
RAID:
Supported mdraid levels: raid6 raid5 raid4 linear multipath raid0 raid1 raid10
Device-1: md0 type: mdraid level: raid-5 status: active size: 5.46 TiB
Info: report: 3/3 UUU blocks: 5860265984 chunk-size: 512k super-blocks: 1.2 algorithm: 2
Components: Online: 0: sda1 1: sdb1 3: sdc1
Drives:
Local Storage: total: raw: 12.74 TiB usable: 10.01 TiB used: 2.05 TiB (20.5%)
ID-1: /dev/nvme0n1 vendor: Crucial model: CT1000P5SSD8 size: 931.51 GiB speed: 31.6 Gb/s
lanes: 4 type: SSD serial: <filter> rev: P4CR311 temp: 38.9 C scheme: GPT
ID-2: /dev/sda vendor: Toshiba model: DT01ACA300 size: 2.73 TiB speed: 6.0 Gb/s type: HDD
rpm: 7200 serial: <filter> rev: ABB0 scheme: GPT
ID-3: /dev/sdb vendor: Toshiba model: DT01ACA300 size: 2.73 TiB speed: 6.0 Gb/s type: HDD
rpm: 7200 serial: <filter> rev: ABB0 scheme: GPT
ID-4: /dev/sdc vendor: Toshiba model: DT01ACA300 size: 2.73 TiB speed: 6.0 Gb/s type: HDD
rpm: 7200 serial: <filter> rev: ABB0 scheme: GPT
ID-5: /dev/sdd type: USB vendor: Crucial model: CT4000P3 PSSD8 P9CR size: 3.64 TiB type: SSD
serial: <filter> rev: 0204 scheme: MBR
Partition:
ID-1: / size: 915.32 GiB used: 384.41 GiB (42.0%) fs: ext4 dev: /dev/nvme0n1p2
ID-2: /boot/efi size: 511 MiB used: 6.1 MiB (1.2%) fs: vfat dev: /dev/nvme0n1p1
ID-3: /home size: 5.41 TiB used: 1.68 TiB (31.0%) fs: ext4 dev: /dev/md0
Swap:
ID-1: swap-1 type: file size: 2 GiB used: 0 KiB (0.0%) priority: -2 file: /swapfile

CUDA is only available on Nvidia GPUs. It is part of the architecture of the cards and is not something that you can just install on other GPUs.

Thank you Charles for your answer. That's what I understood from the majority of my searches. However ZLUDA is a free alternative that seems to be usable with AMD GPUs... Any experienced user being knowledgable?

Something is off with your config. The Radeon VII is still a very capable GPU due to its very good compute capabilities and 16GB of HBM2 memory with 1TB bandwidth.

20 hours for 1 hour HD timeline sounds waaaaay off.

Something's not installed properly in your Linux config.

As the devs said, there is no difference between OpenCL and CUDA for Resolve. They do the same thing.