Your system does not have enough RAM for your workload. ~6 GiB of usable memory is simply not enough for a Windows system today. You need at least 8 GiB. Depending on the tasks you perform (like audio/image/video editing) a lot more may be necessary. (The “missing” RAM in your case is reserved for the integrated GPU. It cannot work without a portion of your RAM.)
Chrome is not exactly memory-efficient. This means all other Chromium-based browsers, like Edge, aren’t either. There’s only really one alternative: Firefox. It uses ever so slightly less memory.
As your RAM fills up, the computer will move data from RAM to the disk to save memory (this is called paging, and the file used on disk is the page file). Thus, actual usage of the page file starts to intensify. You can think of the page file as an extension to your physical memory, but located on your HDD/SSD. (In reality, it’s a lot more complicated.) The system has to use it when physical memory is largely filled. Here’s the next problem with your system: It still has an HDD. Usually, it’d just be a tad slow, but when loaded with lots of random access to the page file, your system will all but grind to a halt.
So there are two potential upgrades. Both would tremendously speed up your computer. Switching to a SSD should be relatively easy. Maybe the system even has a free M.2 slot, meaning you could keep the HDD for bulk storage. More precise information could be available with the exact model number. Upgrading RAM is less likely to be possible, because more and more laptops come with RAM soldered to the mainboard. However, if it fits an HDD, it could work. Again, better information might be available with the exact model number.
Unfortunately, what you provided is not the model number but something else. Check with the guide on how to find the model number to get the right number (make sure to include the portion after the dash, it contains the specific configuration.)
However, going by the model family (X509/M509), ASUS offers service manuals with detailed instructions on how to change/upgrade the vital components: 2.5″ HDD/SSD, M.2 SSD, RAM.
This model series apparently comes with 4 GiB of soldered-on memory + 4 GiB of DDR4 PC4-19200 2400MHz Non-ECC SODIMM memory. The latter you can freely upgrade up to a total of 12 GiB (or 20 GiB, depending on who you ask).
Because this model series is also available with M.2 SSDs, you can install any NVMe M.2 2280 SSD, optionally while also keeping your hard drive. (I recommend removing it though: Using only SSDs will reduce risk to your data in case of fall damage etc.)
Important: Before proceeding with any upgrades, use the guide on how to find the serial number and use that in ASUS’ support portal to make sure these manuals apply to your device. Do not share your device’s serial number on Super User.
