Font problem

can you make a screenshot of what you think is not correct. When i look to your site with chrome or firefox or safari – all browsers are with no major differences

It sounds a bit as if CORS is the reason why – but i can not see such “glyphs” on your page.
if it is a CORS Problem ( Cross-Origin Resource Sharing ) you can solve it by adding this to your htaccess file on root directory of your installation ( if you are running on an Apache Server)

<FilesMatch "\.(eot|otf|svg|ttf|woff|woff2)$">
<IfModule mod_headers.c>
Header set Access-Control-Allow-Origin "*"
</IfModule>
</FilesMatch>

on IIS Server Installations it comes to web.config file:

<system.webServer>
  <httpProtocol>
    <customHeaders>
      <add name="access-control-allow-origin" value="*" />
      <add name="access-control-allow-headers" value="content-type" />
    </customHeaders>
  </httpProtocol>
</system.webServer>

But this seems not to be CORS conflict but a Charset Conflict:
We Germans got it with our ö, ü, ä etc

Read here: https://kriesi.at/support/topic/german-umlauts-and-icons-arent-shown-correctly/

Login with ftp and look for wp-config.php

If there is in it:

define('DB_CHARSET', 'utf8');
define('DB_COLLATE', '');

– replace it with:

define('DB_CHARSET', '');
define('DB_COLLATE', '');

if it is not in the wp-config.php
just try first with

define('DB_CHARSET', 'utf8');
define('DB_COLLATE', '');

https://kriesi.at/support/topic/german-umlauts-and-icons-arent-shown-correctly/#post-864457

try first this above – only if it does not work go on reading
__________-

so you have ftp access to your root directory?
Login. Some ftp clients do not show hidden files on default it must be activated sometimes.
if the charset can not solve it maybe you try the CORS thing:
Filezilla f.e. under Menu – Server – list hidden files.
the htaccess file is a hidden file and has a dot infront of it and no extension.
you can download it – rename it to a file without dot and with extension txt so that there is htaccess.txt.
Open it with a good text editor: sublime text on mac or notepad++ for windows.
Add this code above to it if your provider server is on apache:

<FilesMatch "\.(eot|otf|svg|ttf|woff|woff2)$">
<IfModule mod_headers.c>
Header set Access-Control-Allow-Origin "*"
</IfModule>
</FilesMatch>

upload that file again to your root. rename the existing .htaccess to htaccess.bak ( or something you can remind well) – rename the newly uploaded file to :
.htaccess (without extension)

WordPress character encoding mismatch

The point is that wordpress (newer versions) uses utf-8 charset encoding.
If – on different reasons this could happen – you are using on your database a different charset (latin-1 etc pp) these troubles could happen.
this is known as the double utf-8 Encoding problematc.

If these little changes of the wp-config file do not solve the problem – or change the problem to another one – you have to edit the tables in your database.
there are some plugins doing this.

https://www.tipsandtricks-hq.com/how-to-fix-the-character-encoding-problem-in-wordpress-1480

If the code above in your wp-config.php does not do the trick allone : see here a detailed how to.
https://theblogpress.com/blog/seeing-weird-characters-on-blog-how-to-fix-wordpress-character-encoding-latin1-to-utf8/

On some tips in the internet the lines must be outcoded by //

//define('DB_CHARSET', 'utf8');
//define('DB_COLLATE', '' );

so my tip with outcoding those default lines in wp-config.php solves the problem.
this is nice to know – because on the former thread the participant don’t give us positiv feedback.