Quite often on laptops in addition to Control and Shift and Alt there are color coded keys for extra functions, so you use one of those and then can get a new set of symbols to choose from.

I use a wide and heavy keyboard from Unicomp that emulates the IBM Selectric typewriter keyboard. It has the symbols you seem to be missing: | and \ and possibly ~ or `. One thing I never use is the key a next to the right alt key that replaces a mouse right click anywhere on the desktop or within a document or browser to get a dialog box. This keyboard is so well-made that repeated use of particular keys doesn't wear off the symbol, though those keys are more polished than the rest.

You can use another keyboard with your laptop, either a USB one to plug in or if it's new enough and set up there are Bluetooth devices. My keyboard has no emojis, I use html if I need symbols. I tried the Windows + . and see the choices (which, as noted, won't display on Mudcat. Gotta do html or ascii code for those.)