Linux uses RAM for caching whenever possible, so high RAM usage is not abnormal by itself.
The kernel should free caching memory for applications when necessary. The question of your saturation is whether it fails to do so, or if there is an application grabbing all the memory…
You could check system logs for some clues: [HowTo] Find error logs
Also, please use preformatting whenever possible: [HowTo] Use preformatting in a forum post
Another option would be to install a OOM-killer daemon, which will kill the highest consuming thread if memory saturates. They also usually leave a system log for which process they kill.
https://wiki.archlinux.org/title/Improving_performance#Improving_system_responsiveness_under_low-memory_conditions