htaccess extract path only from THE_REQUEST into a variable - .htaccess

Question

This should be rather simple, but after trying for several hours and also searching everywhere, all the related answers do not suffice.
I have this so far:
RewriteCond %{THE_REQUEST} /([a-zA-Z0-9-_/\.]+)?
RewriteRule ^(.*)$ - [E=TRGT:%1]
What the match should be doing is the following:
for URL example.com it should contain nothing, or not be defined
for URL example.com/ it should contain nothing, or not be defined
for URL example.com/some-word it should contain some-word
for URL example.com/some-word/ it should contain some-word
for URL example.com/some-word/?foo=bar it should contain some-word
for URL example.com/another_word/ it should contain another_word
for URL example.com/folder/file.ext it should contain folder/file.ext
for URL example.com/some/other.dot?bar=foo it should contain some/other.dot
for URL example.com/thing.ext/?foo=bar&bar=foo it should contain thing.ext
What I have so far seems to be working, except for when the request ends in some/ -or some/?thing=wat .. then it contains some/
I think I'm missing something really simple; any help will be appreciated, thank you.
UPDATE
I've managed to achieve these exact requirements with the following code, but, after trying many ways to do it in a 1-liner it fails horribly, so I did it in several lines:
RewriteCond %{THE_REQUEST} (?<=\s)(.*?)(?=\s)
RewriteRule ^(.*)$ - [E=HREFPATH:%1]
RewriteCond %{ENV:HREFPATH} (^.*)?\?
RewriteRule ^(.*)$ - [E=HREFPATH:%1]
RewriteCond %{ENV:HREFPATH} /(.*)
RewriteRule ^(.*)$ - [E=HREFPATH:%1]
RewriteCond %{ENV:HREFPATH} (.*)/$
RewriteRule ^(.*)$ - [E=HREFPATH:%1]
If anybody can reduce that to a s3xy 1(or 2)-liner I will choose your answer; thanks in advance.

Answer 1

Based on the accepted answer here the following fulfills the requirements of the question:
RewriteCond %{THE_REQUEST} \s/+([^?]*?)/*[\s?]
RewriteRule ^ - [E=HREFPATH:%1]