so AI is recommending that on top of setting preset-vaapi, I also add:

environment.LIBVA_DRIVER_NAME = "radeonsi";
  serviceConfig = {
    SupplementaryGroups = ["render" "video"];
    AmbientCapabilities = "CAP_PERFMON";
  };

  systemd.services.frigate = {
    environment.LIBVA_DRIVER_NAME = "radeonsi";
    serviceConfig = {
      SupplementaryGroups = ["render" "video"] ; # for access to dev/dri/*
      AmbientCapabilities = "CAP_PERFMON";
    };
  };

Jan 13 20:42:36 frigate systemd[1]: Starting frigate.service...
Jan 13 20:42:36 frigate systemd[1]: Started frigate.service.
Jan 13 20:42:37 frigate frigate[9827]: 2025-01-13 20:42:37.084120: I tensorflow/core/platform/cpu_feature_guard.cc:210] This TensorFlow binary is optimized to use available CPU instructions in performance->
Jan 13 20:42:37 frigate frigate[9827]: To enable the following instructions: AVX2 FMA, in other operations, rebuild TensorFlow with the appropriate compiler flags.
Jan 13 20:42:40 frigate frigate[9827]: /nix/store/cgbfczq9sp6sd5h1dd20zkf5fk2k5byg-frigate-0.14.1/lib/python3.12/site-packages/frigate/util/services.py:299: SyntaxWarning: invalid escape sequence '\d'
Jan 13 20:42:40 frigate frigate[9827]:   for result in re.findall('"Video/\d":{[a-z":\d.,%]+}', reading):
Jan 13 20:42:41 frigate frigate[9901]: [2025-01-13 20:42:41] frigate.app                    INFO    : Starting Frigate (0.14.1)
Jan 13 20:42:41 frigate frigate[9901]: [2025-01-13 20:42:41] frigate.app                    INFO    : Creating directory: /var/cache/frigate/model_cache
Jan 13 20:42:41 frigate frigate[9901]: [2025-01-13 20:42:41] frigate.util.config            INFO    : Checking if frigate config needs migration...
Jan 13 20:42:41 frigate frigate[9901]: [2025-01-13 20:42:41] frigate.util.config            ERROR   : Config file is read-only, unable to migrate config file.
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] peewee_migrate.logs            INFO    : Starting migrations
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] peewee_migrate.logs            INFO    : There is nothing to migrate
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] frigate.app                    INFO    : Recording process started: 9919
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] frigate.app                    INFO    : Recording process started: 9928
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] frigate.app                    INFO    : go2rtc process pid: 1042
Jan 13 20:42:42 frigate frigate[9901]: [2025-01-13 20:42:42] detector.coral                 INFO    : Starting detection process: 9947
Jan 13 20:42:43 frigate frigate[9901]: [2025-01-13 20:42:43] frigate.app                    INFO    : Output process started: 9949
Jan 13 20:42:43 frigate frigate[9901]: [2025-01-13 20:42:42] frigate.detectors.plugins.edgetpu_tfl INFO    : Attempting to load TPU as usb
Jan 13 20:42:43 frigate frigate[9901]: [2025-01-13 20:42:43] frigate.app                    INFO    : Camera processor started for mycamerastream: 9962
Jan 13 20:42:43 frigate frigate[9901]: [2025-01-13 20:42:43] frigate.app                    INFO    : Capture process started for mycamerastream: 9965
Jan 13 20:42:44 frigate frigate[9901]: [2025-01-13 20:42:44] frigate.video                  ERROR   : mycamerastream: Unable to read frames from ffmpeg process.
Jan 13 20:42:44 frigate frigate[9901]: [2025-01-13 20:42:44] frigate.video                  ERROR   : mycamerastream: ffmpeg process is not running. exiting capture thread...
Jan 13 20:42:45 frigate frigate[9901]: [2025-01-13 20:42:45] frigate.util.services          ERROR   : Unable to poll vainfo: b"error: XDG_RUNTIME_DIR is invalid or not set in the environment.\nerror: can't>
Jan 13 20:42:45 frigate frigate[9901]: [2025-01-13 20:42:45] frigate.util.services          ERROR   : Unable to poll intel GPU stats: No device filter specified and no discrete/integrated i915 devices found
Jan 13 20:42:46 frigate frigate[9947]: INFO: Created TensorFlow Lite XNNPACK delegate for CPU.
Jan 13 20:42:46 frigate frigate[9901]: [2025-01-13 20:42:46] frigate.detectors.plugins.edgetpu_tfl INFO    : TPU found
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] watchdog.mycamerastream           ERROR   : Ffmpeg process crashed unexpectedly for mycamerastream.
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] watchdog.mycamerastream           ERROR   : The following ffmpeg logs include the last 100 lines prior to exit.
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : [AVHWDeviceContext @ 0x356987c0] Failed to initialise VAAPI connection: -1 (unknown libva error).
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : Device creation failed: -5.
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : [vist#0:0/h264 @ 0x356a2a00] [dec:h264 @ 0x35623e80] No device available for decoder: device type vaapi>
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : [vist#0:0/h264 @ 0x356a2a00] [dec:h264 @ 0x35623e80] Hardware device setup failed for decoder: Input/ou>
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : Error opening output file pipe:.
Jan 13 20:43:03 frigate frigate[9901]: [2025-01-13 20:43:03] ffmpeg.mycamerastream.detect      ERROR   : Error opening output files: Input/output error
Jan 13 20:43:04 frigate frigate[9901]: [2025-01-13 20:43:04] frigate.video                  ERROR   : mycamerastream: Unable to read frames from ffmpeg process.