In that case, I'm not sure.
I always make such symbols using Fcitx.
So I type for example "30do", hit space to get through the list until I get to "30℃", or I type "marukyuu" to get ⑨, or "sikaku" for ■ and □, or "rosiamoji" for the entire list of Russian characters to choose from, or "ahya" for (ﾟ∀ﾟ), or "nippon" for ??, and so on.
I honestly didn't even know there was some key for that to do the same thing.
I always make such symbols using Fcitx.
So I type for example "30do", hit space to get through the list until I get to "30℃", or I type "marukyuu" to get ⑨, or "sikaku" for ■ and □, or "rosiamoji" for the entire list of Russian characters to choose from, or "ahya" for (ﾟ∀ﾟ), or "nippon" for ??, and so on.
I honestly didn't even know there was some key for that to do the same thing.
母語は日本語ですが、英語も喋れます（ｒｙ