[Samsung Galaxy Watch 4] adfree:
Few Commands via ADB...

This shows some infos about partition layout... PIT

freshbl:/ $ ls /dev/block/platform/10500000.dwmmc0/by-name/ -la
total 0
drwxr-xr-x 2 root root 760 2021-09-01 01:34 .
drwxr-xr-x 3 root root 840 2021-09-01 01:34 ..
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 blcmd -> /dev/block/mmcblk0p17
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 boot -> /dev/block/mmcblk0p18
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 bota -> /dev/block/mmcblk0p6
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 cache -> /dev/block/mmcblk0p33
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 cp_debug -> /dev/block/mmcblk0p35
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 cpefs -> /dev/block/mmcblk0p4
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 dtbo -> /dev/block/mmcblk0p20
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 ebl -> /dev/block/mmcblk0p10
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 efs -> /dev/block/mmcblk0p1
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 fmp_selftest -> /dev/block/mmcblk0p28
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 keydata -> /dev/block/mmcblk0p26
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 keyrefuge -> /dev/block/mmcblk0p25
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 keystorage -> /dev/block/mmcblk0p11
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 ldfw -> /dev/block/mmcblk0p7
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 metadata -> /dev/block/mmcblk0p27
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 misc -> /dev/block/mmcblk0p14
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 nad_refer -> /dev/block/mmcblk0p12
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 omr -> /dev/block/mmcblk0p34
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 optics -> /dev/block/mmcblk0p32
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 param -> /dev/block/mmcblk0p5
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 persistent -> /dev/block/mmcblk0p22
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 prism -> /dev/block/mmcblk0p31
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 radio -> /dev/block/mmcblk0p21
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 recovery -> /dev/block/mmcblk0p19
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 reserved2 -> /dev/block/mmcblk0p29
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 sec_efs -> /dev/block/mmcblk0p2
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 steady -> /dev/block/mmcblk0p3
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 super -> /dev/block/mmcblk0p30
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 tzar -> /dev/block/mmcblk0p9
lrwxrwxrwx 1 root root 20 2021-09-01 01:34 tzsw -> /dev/block/mmcblk0p8
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 uh -> /dev/block/mmcblk0p15
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 uhcfg -> /dev/block/mmcblk0p16
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 up_param -> /dev/block/mmcblk0p13
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 userdata -> /dev/block/mmcblk0p36
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 vbmeta -> /dev/block/mmcblk0p23
lrwxrwxrwx 1 root root 21 2021-09-01 01:34 vbmeta_system -> /dev/block/mmcblk0p24

This could record Video.. from Screen... no idea if Root mandatory...

freshbl:/ $ screenrecord --help
Usage: screenrecord [options] <filename>

Android screenrecord v1.3. Records the device's display to a .mp4 file.

Options:
--size WIDTHxHEIGHT
Set the video size, e.g. "1280x720". Default is the device's main
display resolution (if supported), 1280x720 if not. For best results,
use a size supported by the AVC encoder.
--bit-rate RATE
Set the video bit rate, in bits per second. Value may be specified as
bits or megabits, e.g. '4000000' is equivalent to '4M'. Default 20Mbps.
--bugreport
Add additional information, such as a timestamp overlay, that is helpful
in videos captured to illustrate bugs.
--time-limit TIME
Set the maximum recording time, in seconds. Default / maximum is 180.
--display-id ID
specify the physical display ID to record. Default is the primary display.
see "dumpsys SurfaceFlinger --display-id" for valid display IDs.
--verbose
Display interesting information on stdout.
--help
Show this message.

Recording continues until Ctrl-C is hit or the time limit is reached.

This could capture Screenshots via ADB...

freshbl:/ $ screencap --help
screencap: invalid option -- -
usage: screencap [-hp] [-d display-id] [FILENAME]
-h: this message
-p: save the file as a png.
-d: specify the physical display ID to capture (default: 0)
see "dumpsys SurfaceFlinger --display-id" for valid display IDs.
If FILENAME ends with .png it will be saved as a png.
If FILENAME is not given, the results will be printed to stdout.