I inherited an existing (and very problematic) wordpress.org site, and I'm having a hard time understanding the choices/rules the previous owner decided to make regarding the .htaccess file.

I've been trying to google different parts of it and looking at different documentation, but there are some parts I can't find the answer to

I used the htaccess tester and some rules were met, but many rules were not. Testers cannot inspect the 'ifmodule' statement and cannot understand CacheLookup on

# BEGIN LSCACHE
## LITESPEED WP CACHE PLUGIN - Do not edit the contents of this block! ##
<IfModule LiteSpeed>
RewriteEngine on
CacheLookup on
RewriteRule .* - [E=Cache-Control:no-autoflush]
RewriteRule \.litespeed_conf\.dat - [F,L]

### marker CACHE RESOURCE start ###
RewriteRule wp-content/.*/[^/]*(responsive|css|js|dynamic|loader|fonts)\.php - [E=cache-control:max-age=3600]
### marker CACHE RESOURCE end ###

### marker FAVICON start ###
RewriteRule favicon\.ico$ - [E=cache-control:max-age=86400]
### marker FAVICON end ###

### marker WEBP start ###
RewriteCond %{HTTP_ACCEPT} "image/webp"
RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
RewriteCond %{HTTP_USER_AGENT} iPhone.*Version/(\d{2}).*Safari
RewriteCond %1 >13
RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
### marker WEBP end ###

### marker DROPQS start ###
CacheKeyModify -qs:fbclid
CacheKeyModify -qs:gclid
CacheKeyModify -qs:utm*
CacheKeyModify -qs:_ga
### marker DROPQS end ###

</IfModule>
## LITESPEED WP CACHE PLUGIN - Do not edit the contents of this block! ##
# END LSCACHE
# BEGIN NON_LSCACHE
## LITESPEED WP CACHE PLUGIN - Do not edit the contents of this block! ##
## LITESPEED WP CACHE PLUGIN - Do not edit the contents of this block! ##
# END NON_LSCACHE


#Begin Really Simple Security
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTPS} !=on [NC]
RewriteRule ^(.*)$ https://%{HTTP_HOST}/ [R=301,L]
</IfModule>

#End Really Simple Security
# BEGIN WordPress
# The directives (lines) between "BEGIN WordPress" and "END WordPress" are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

First, the testers say

RewriteEngine on

Only the last RewriteEngine line is taken into account

If so, why do you add it for every marked part? Can I omit this?

Also, many of the litespeed rules are not met, but I also recognize that there are some parts that it cannot understand/see

Seems to be missing the "Sample Rules" section and rewrite rules set on litespeed .htaccess

Why might they change some parts of the "suggested" example rules? For example my file says

RewriteCond %{HTTP_ACCEPT} "image/webp"

(Tester cannot check because the variable is unknown to them) But example rewrite rules include [or]

RewriteCond %{HTTP_ACCEPT} "image/webp" [or]

Also, I'm not sure why they decided to include an if statement to check which module? (What are the advantages of these, or can these "ifmodule" tags be removed?)

Finally, this might be a silly question - is "Really Simple SSL" the same as/formerly known as "Really Simple Security"? If so, should I update my .htaccess to the very simple SSL .htaccess guidelines?

I hope this post can also help others trying to configure their sites.