Enabling TRIM is not critical. Just a suggestion.
As for going up to 16GB of RAM. Your Mac is 8 years old. It is not getting any younger. The question is how much will adding 16GB of RAM cost to your budget vs saving that money towards a new Mac. You will need a new system eventually, so you should at least start making budgeting decisions with that in mind.
Uninstalling the Kaspersky should help with the current configuration.
Also to save RAM for your uses, uninstall MalwareBytes until the next time you install something else and want to check if it also did a side-install. That is to say, today the only malware that makes it to Macs is via you being involved in installing it, so you can safely leave MalwareBytes off your system and only install and run it after installing something else and you want to check your system.
Not sure what "App Cleaner Helper SMLoginItem" is but it has a name that makes me worry it is trying to clean things that most likely do not need cleaning. It is also using your RAM, so if you want to live inside your existing RAM, you should consider NOT running a lot of extra stuff all the time. So I would suggest removing this app.
Google Chrome can be a memory hog, so you might consider ONLY Using Chrome for websites that really need Chrome and us Safari (or Firefox) for other the rest. And regardless of which web browser you use, do not keep too many tabs open at once. Again the goal is to conserve RAM so that you are not forcing the system to page and swap to the storage device.
If you minimize your application memory footprint, you can most likely live in 4GB considering you have an SSD already.
But if you want to run lots of other 24/7 background apps, and have lots of concurrent browser tabs open all the time, then by all means, get 16GB of RAM 🙂