Text Formatting ⇒ embedding fonts from special characters

[quickhelp2020]

Hi, I need to submit a thesis to an online library and for this I have to make some changes to my pdf.
One problem that I'm facing is, that all fonts must be embedded.
Adobe Acrobat finds 5 fonts, which are not embedded. I deleted almost everything in adobe and found that the non-embedded fonts originate from special letters, such as \textregistered, \celsius, \beta...
I created the files via Texmaker in windows.

I attached three files for an example. If you compile main.tex, then you will get the pdf with my abbreviations. Here are some greek letters, which are not embedded fonts.

Does anyone know how to embed these fonts?

(Strangely, pdffonts tells me that all fonts are embedded. But I have to follow the rules form the library.)

[quickhelp2020]

Problem solved.
The special characters got embedded as Font Type 3, which is not supported by adobe.

To change them to font type 1 (which is supported by adobe), all I had to do was to install the font package "cm-super".
In Miktex the cm-super package can be easily installed:
open "Miketex console" in the start menu. Go to the tab "packages" and install "cm-super"
Then, type "updmap" in the windows command prompt or in the windows power shell to update the fonts.
Now, LaTeX uses the type 1 instead of the type 3. You don't have to change anything in the .tex-file.