Need help correctly configuring .htaccess for HTTPS - .htaccess

Question

I am trying to configure and write my .htaccess file correctly. There are some things I already tried, but somehow they dont all work out.
I am trying to accomplish the following redirects:
Redirect from HTTP to HTTPS for all folders, including subfolders
Remove ".html" endings so the url shows www.domain.com/photos instead of www.domain.com/photos.html
Remove "index.html" when on home page, so it only shows www.domain.com
Some things work, but when going in a subdirectory like www.domain.com/sub, the page changes from HTTPS to HTTP.
Also, when accessing the page via HTTPS, it doesnt correctly load the font, that is specified in the HTML file
()
See my code below:
<IfModule mod_rewrite.c>
AddType text/x-component .htc
RewriteEngine On
RewriteBase /
RewriteCond %{HTTPS} !=on
# This checks to make sure the connection is not already HTTPS RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]
# This rule will redirect users from their original location, to the same location but using HTTPS. # i.e. http://www.example.com/foo/ to https://www.example.com/foo/ # The leading slash is made optional so that this will work either in httpd.conf or .htaccess context
# remove .html; use THE_REQUEST to prevent infinite loops
RewriteCond %{THE_REQUEST} ^GET\ (.*)\.html\ HTTP
RewriteRule (.*)\.html$ $1 [R=301]
# remove index
RewriteRule (.*)/index$ $1/ [R=301]
# remove slash if not directory
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} /$
RewriteRule (.*)/ $1 [R=301]
# add .html to access file, but don't redirect
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteCond %{REQUEST_URI} !/$
RewriteRule (.*) $1\.html [L]
</IfModule>

Answer 1

I figured it out and it works so far:
<IfModule mod_rewrite.c>
AddType text/x-component .htc
RewriteEngine On
RewriteBase /
# Redirect to www
RewriteCond %{HTTP_HOST} !^www\.domain\.ch [NC,OR]
# Redirect to https
RewriteCond %{HTTP:CF-Visitor} '"scheme":"http"'
RewriteRule ^ https://www.domain.ch%{REQUEST_URI} [NE,R=301,L]
# remove .html; use THE_REQUEST to prevent infinite loops
RewriteCond %{THE_REQUEST} ^GET\ (.*)\.html\ HTTP
RewriteRule (.*)\.html$ $1 [R=301]
# remove index
RewriteRule (.*)/index$ $1/ [R=301]
# remove slash if not directory
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} /$
RewriteRule (.*)/ $1 [R=301]
# add .html to access file, but don't redirect
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteCond %{REQUEST_URI} !/$
RewriteRule (.*) $1\.html [L]
</IfModule>