In Fedora I used to type the ≈ (U2248) pretty much on the daily basis.I did it by pressing the Compose Key (Right Alt in my case) and then the ~ key twice.
But several months ago it stopped working.
The compose key works: it types other symbols correctly, e.g. 450⁰ and when I try to use the ~ it also causes the cursor to go into a sort-of waiting mode. But when I press the ~ the second time: the 'waiting mode' is canceled and no text has been entered (just like when the user typed an invalid compose key sequence).
So it's not an issue with the compose key.
Could anyone suggest something? Thank you.