@Val what I suggest is to open a topic on our nodered category. There are plenty of people who can help look at the flows and the necessary debug to help optimise and get around this behaviour.
The watchdog, if it is being triggered, can be raised.
First, check the system logs in /var/log - it will contain entries for watchdog reboots if this is the cause.
Post this advanced widget, it is a barometer for overload - the GX by default is optimised to keep a vebus system running:
Via ssh you can also run “top” which will show your CPU utilisation.
If these metrics confirm load as the main factor, there is always some adjustments that can be made to flows to lower the load and restore stability.
(The forum allows you export the json from nodered and paste in with tags so it displays correctly)