Htaccess order of mod modules - .htaccess

Question

I'm writing a script that will alter the roots .htaccess file to block user agents (yandex in this example). I wrote it to use the setenvif command but it wasn't working. Via another post here I was told it was because a redirect prior to the command was causing it to fail due to the .htaccess file being reloaded. I added a rewritecond statement to do the block and it worked. If I place the setenvif statement at the top of the file it also works correctly.
In researching this others have stated that mod_rewrite is handled before mod_alias but I can't find any mention of when mod_setenvif is handled. There also seems to be little information regarding the order of things in the .htaccess file in general. Below is an example of the things in my .htaccess file. Even as a novice I can see it is not ordered well.
But before I deal with that I wanted to see where to properly place the setenvif statement?
And am I correct in assuming that any setenvif, rewritecond and deny statement that causes a block or redirect to another site should be placed at the top?
Options +FollowSymLinks -Indexes
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} "WOW32" [NC,OR]
RewriteCond %{HTTP_USER_AGENT} "WOW64" [NC]
RewriteRule ^(.*)$ - [F]
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://example.com/$1 [R,L]
redirect 301 /about_us.php https://example.com/about.html
<Files test.html>
order allow,deny
</Files>
<FilesMatch "\.(inc|tpl|h|ihtml|sql|ini|conf|class|bin|spd|theme|module|exe)$">
</FilesMatch>
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access plus 1 year"
</IfModule>
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE application/javascript
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
Header append Vary User-Agent
</IfModule>
ErrorDocument 400 /server_error.php?id=400
order allow,deny
deny from 1.2.3.4/32
allow from all
SetEnvIfNoCase User-Agent "^yandex$" my_block
<IfModule !authz_core_module>
Order Allow,Deny
Allow from ALL
Deny from env=my_block
</IfModule>
RewriteCond %{HTTP_USER_AGENT} ^.*(yandex).*$ [NC,OR]