"What products should I update? The processor, memory, battery?
Unfortunately the only things that you can "Upgrade or Update" Are the SSD & The Battery as the CPU & RAM are soldered onto the board and cannot be removed or replaced easily. The last supported OS is 11.7.10 Big Sur. If the laptop is running a bit slow then maybe it is time for a [link|https://support.apple.com/en-ph/guide/mac-help/mh27903/mac|clean install] to freshen it up. Canva can be [link|https://www.canva.com/download/mac/|downloaded from here] although it still needs a log in to fully function I think it may help improve the experience. These are great MacBooks and I think they are still very usable.