I'm doing this on Mac using launchctl. Can include the actual plist as well. Really basic though. Runs every 10 seconds. I turn it off when not running OBS. (launchctl unload screencapture-obs-agent.plist)

screencapture-obs-agent.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>EnvironmentVariables</key>
	<dict>
		<key>PATH</key>
		<string>/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/Frameworks/Mono.framework/Versions/Current/Commands:/usr/local/sbin</string>
	</dict>
	<key>Label</key>
	<string>screencapture-obs-agent</string>
	<key>ProgramArguments</key>
	<array>
		<string>/Users/makeanothertelephonecall/Dropbox/~Local/bin/screencapture-obs-agent.sh</string>
	</array>
	<key>RunAtLoad</key>
	<false/>
	<key>StartInterval</key>
	<integer>2</integer>
</dict>
</plist>

screencapture-obs-agent.sh

# Thanks to @Nick Wong @nickwongv for this idea!

# -S doesn't seem necessary. Doing whÎole desktop, not a selection
# -m will get main monitor. Not active though, right?

screencapture -Cx /Volumes/mmSKLegionFSpace/NAS/_sharing/accountability/default_capture_1.png

# If want to run another one again with a delay vs only having macOS launch agent control time
# a 2nd 3 sec delay
# screencapture -T 3 -Cx /Volumes/mmSKLegionFSpace/NAS/_sharing/accountability/default_capture_1.png