Thank you for your query.
To be honest, in your particular case you have installed both packages DDNS and SNMP. The total flash memory of RUT950 is 4.2MB. For example, DDNS package on its own is 1.8 MB and SNMP 557KB, in total that is around 2.4MB of flash usage.(as around 10-12% is used by default even on a newly reseted device) This could result in around 65% flash usage. The problem that I looked into at the forum query 40441 was in regards to a problem where package manager didn't allow to install any packages after reaching flash usage of around 48-50 %.
This problem is known and a workaround was provided there. In addition, a test firmware could be provided that would allow to install the packages.(If needed, please send me a private message). In general, this should come with our 7.2 FW release. Unfortunately, an exact date is currently unknown.
However, the test firmware would not resolve the flash and Ram usage of your device. As mentioned, considering the amount of Flash memory available, the flash usage seems normal to me. In regards to your Ram usage, my device had around 50-55 % with the same packages installed, so It could be around 60% when using the device. The reason behind this is that there are a lot of default processes running on the device in the background(RutOS processes). In addition, RUT950 has a very low RAM memory in general - 128mb, this is a factor as well why the percentage is so high. However, the device should function normally with such RAM usage.
If it doesn't, Could you please elaborate a little bit more on "device running very unstable", does it reboot? disconnects? In addition, a Could you please attach a troubleshoot file when this issue occurs.
For this please navigate to System -> Backup -> Troubleshoot -> Download troubleshoot file and forward it to me via private message.