Did you manage to get the serial connection working?
in my case, I got the following errors using the followinfg command. I tried adding sudo in front, commands not found.
ros2 launch mavros apm.launch fcu_url:=///dev/ttyAMA1:921600
[mavros_node-1] [WARN] [1703040975.607465545] [mavros.sys]: VER: your FCU don’t support AUTOPILOT_VERSION, switched to default capabilities
[mavros_node-1] [INFO] [1703040995.594057491] [mavros.mavros_router]: link[1000] trying to reconnect…
[mavros_node-1] [ERROR] [1703040995.594602266] [mavros.mavros_router]: link[1000] reconnect failed: DeviceError:serial:open: Permission denied
sudo: ros2: command not found
sudo: source: command not found
[edit]
oh I need to chmod.
sudo chmod 666 /dev/ttyAMA1
[mavros_node-1] [INFO] [1703043435.797725348] [mavros.mavros]: MAVROS UAS via /uas1 started. MY ID 1.191, TARGET ID 1.1
[mavros_node-1] [INFO] [1703043435.893891732] [mavros.mavros_router]: link[1001] detected remote address 1.191
[mavros_node-1] [WARN] [1703043435.939497584] [mavros.cmd]: CMD: Unexpected command 520, result 0
[mavros_node-1] [INFO] [1703043435.943280407] [mavros.geofence]: GF: Using MISSION_ITEM_INT
[mavros_node-1] [INFO] [1703043435.943579029] [mavros.rallypoint]: RP: Using MISSION_ITEM_INT
[mavros_node-1] [INFO] [1703043435.943688081] [mavros.mission]: WP: Using MISSION_ITEM_INT
[mavros_node-1] [INFO] [1703043435.943783875] [mavros.sys]: VER: 1.1: Capabilities 0x000000000000fbef
[mavros_node-1] [INFO] [1703043435.943882428] [mavros.sys]: VER: 1.1: Flight software: 040300ff (3137623834343339)
[mavros_node-1] [INFO] [1703043435.943941260] [mavros.sys]: VER: 1.1: Middleware software: 00000000 (0000000000000000)
[mavros_node-1] [INFO] [1703043435.944166254] [mavros.sys]: VER: 1.1: OS software: 00000000 (6430656435653636)
[mavros_node-1] [INFO] [1703043435.944273658] [mavros.sys]: VER: 1.1: Board hardware: 008c0000
[mavros_node-1] [INFO] [1703043435.944323546] [mavros.sys]: VER: 1.1: VID/PID: 2dae:1016
[mavros_node-1] [INFO] [1703043435.944360970] [mavros.sys]: VER: 1.1: UID: 0000000000000000
[mavros_node-1] [WARN] [1703043436.006865604] [mavros.time]: TM: Wrong FCU time.
[mavros_node-1] [INFO] [1703043436.506899043] [mavros.mavros]: CON: Got HEARTBEAT, connected. FCU: ArduPilot
[mavros_node-1] [INFO] [1703043436.507231312] [mavros.mission]: WP: detected enable_partial_push: 1
[mavros_node-1] [INFO] [1703043437.523120229] [mavros.sys]: VER: 1.1: Capabilities 0x000000000000fbef
[mavros_node-1] [INFO] [1703043437.523386092] [mavros.sys]: VER: 1.1: Flight software: 040300ff (93448b71)
[mavros_node-1] [INFO] [1703043437.523461535] [mavros.sys]: VER: 1.1: Middleware software: 00000000 ( )
[mavros_node-1] [INFO] [1703043437.523514255] [mavros.sys]: VER: 1.1: OS software: 00000000 (66e5de0d�-��)
[mavros_node-1] [INFO] [1703043437.523562032] [mavros.sys]: VER: 1.1: Board hardware: 008c0000
[mavros_node-1] [INFO] [1703043437.523610364] [mavros.sys]: VER: 1.1: VID/PID: 2dae:1016
[mavros_node-1] [INFO] [1703043437.523683806] [mavros.sys]: VER: 1.1: UID: 0000000000000000
[mavros_node-1] [ERROR] [1703043442.256876783] [mavros.sys]: FCU: PreArm: Throttle below failsafe
[mavros_node-1] [ERROR] [1703043442.257912717] [mavros.sys]: FCU: PreArm: Hardware safety switch
[mavros_node-1] [ERROR] [1703043442.258968541] [mavros.sys]: FCU: PreArm: Battery 1 below minimum arming voltage
[mavros_node-1] [INFO] [1703043446.508945540] [mavros.home_position]: HP: requesting home position
[mavros_node-1] [INFO] [1703043446.515052189] [mavros.sys]: FCU: ArduCopter V4.3.0 (93448b71)
[mavros_node-1] [INFO] [1703043446.516115457] [mavros.sys]: FCU: ChibiOS: 66e5de0d
[mavros_node-1] [INFO] [1703043446.516858733] [mavros.sys]: FCU: CubeOrange 001D002D 32315108 38323831
[mavros_node-1] [INFO] [1703043446.517399126] [mavros.sys]: FCU: RCOut: PWM:1-8 DS600:9-12 PWM:13-14
[mavros_node-1] [INFO] [1703043446.518137050] [mavros.sys]: FCU: IMU0: fast sampling enabled 8.0kHz/2.0kHz
[mavros_node-1] [INFO] [1703043446.518518762] [mavros.sys]: FCU: IMU1: fast sampling enabled 9.0kHz/2.3kHz
[mavros_node-1] [INFO] [1703043446.519244983] [mavros.sys]: FCU: IMU2: fast sampling enabled 9.0kHz/2.3kHz
[mavros_node-1] [INFO] [1703043446.519585140] [mavros.sys]: FCU: Frame: QUAD/X
[mavros_node-1] [INFO] [1703043451.518598889] [mavros.mission]: WP: mission received
[mavros_node-1] [INFO] [1703043456.519703880] [mavros.rallypoint]: RP: mission received
[mavros_node-1] [INFO] [1703043461.519426965] [mavros.geofence]: GF: mission received
[mavros_node-1] [INFO] [1703043466.715644111] [mavros.param]: PR: parameters list received
[mavros_node-1] [ERROR] [1703043473.256038877] [mavros.sys]: FCU: PreArm: Throttle below failsafe
[mavros_node-1] [ERROR] [1703043473.256735284] [mavros.sys]: FCU: PreArm: Hardware safety switch
[mavros_node-1] [ERROR] [1703043473.257150755] [mavros.sys]: FCU: PreArm: Battery 1 below minimum arming voltage
[mavros_node-1] [WARN] [1703043496.505907427] [mavros.time]: TM: Wrong FCU time.
[mavros_node-1] [ERROR] [1703043504.255434445] [mavros.sys]: FCU: PreArm: Throttle below failsafe
[mavros_node-1] [ERROR] [1703043504.256417975] [mavros.sys]: FCU: PreArm: Hardware safety switch
[mavros_node-1] [ERROR] [1703043504.256974571] [mavros.sys]: FCU: PreArm: Battery 1 below minimum arming voltage