If you don’t mind that your url rather looks like a /directory/ instead of a page, this is what i just found:
01 install and activate PermaLink Redirect https://fucoder.com/code/permalink-redirect/
02 get the id of the page that should work as your homepage
03 open options -> permalinks
04 activate ‘userdefined’ and enter /%postname% in the field below
05 set /. as the category base
06 open your .htaccess and add the following:
DirectoryIndex index.php?page_id=X # replace X with the ID of the desired page
# Either WordPress already did it for you or enter this manually at the bottom of your .htaccess:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
Now your visitors are redirected to domain.xx/pageslug/ when they visit domain.xx/
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Now for your second question:
Just enter a number in the Page Order field in the edit screen of your page. For your convenience, you should leave some room to move pages around, e.g. setting the numbers in steps of 10,20,30, …