With the rules in your current order a request for example.com/index.html is first redirected to www.example.com/index.html and then to www.example.com/ in a two-step redirection chain.
You want to redirect in a single step. You do that by reversing the rule order and by ensuring the target of the index redirect specifies the full URL including protocol and hostname.
Change all Redirect and RedirectMatch directives to use RewriteRule.
Redirect 301 /about.html http://www.google.com
RewriteRule ^about\.html http://www.google.com/ [R=301,L]
with ^ on pattern start, escaping on literal period, trailing slash on target and [R=301] and [L] flags.
Order your rules from most specific to most general.
Escape literal periods in RegEx patterns.
Comment your code.
Leave a blank line after each RewriteRule.
^example.com [NC] with