Hi, chattrhand. I use brave-browser and have no problems entering special symbols. It seems something is unwell with your keyboard settings. Having to copy-paste those special symbols sounds like the most painful workaround imaginable.
On my laptop, which has a standard US keyboard, I can put AltGr ("level 3") and compose keys anywhere I want. If I want those keys on the right Alt and right Ctrl keys, for example, I just have to issue this command in a terminal:
$ setxkbmap -layout us -variant intl -option lv3:ralt,compose:rctrl
Now to create the @ symbol with the compose key, I can press and release right Ctrl, then A, then T. Note that the A and T must be capitalized using the Shift key.
PS1: Note that the setxkbmap command does not survive reboots. You have to issue the command with each boot. To automate this, you can create a script in ~/.X.d
PS2: Rich, I realize that this post is not directly relevant to the topic of the thread. Please feel free to move it (with the post that it is referring to) somewhere else.