Ordinarily that is “0%” used. The only reason there is no specific limiting of the use of swap space is that it doesn’t get used, so limiting it isn’t on the radar.
There’s a lot of hard work going on trying to minimise the disk writes by moving things that write to disk, in to RAM. That seems pointless if the RAM is then extented to use swap out of our control.
Sorry I don’t watch “how to video’s” they tend to be way too slow to keep my attention.
There is a whole discussion on emonPi ssh here “emonPi SSH disabled by default” and AFAIA the default Raspian method to enable via blank “ssh” file in the boot partition is still active on the emonSD. See section 3 here “Raspberry Pi Documentation - Remote access”.
Using the hdmi port, that would involve removing the Pi from it’s case as the hdmi port is on the side edge.
Not without editing /boot/cmdline.txt and stripping down the emonPi add-on board from the RPi as the GPIO serial UART is used for the emonpi add-on board, the serial console is disabled.
Unfortunately, if the button method doesn’t work, you need a torx screwdriver whatever method you choose. I would opt for the easiest option of just putting a blank “ssh” file on the boot partition from another PC by putting the sdcard in a usb card reader.