Since you have 5000 URLs you should not be using redirections in .htaccess. This is very slow since that file is read and parsed each and every time any URL on your site is being accessed; not just pages, but also CSS files, JavaScript files, images, etc. You do, indeed, need a tool to manage redirections and Admin Tools is as good as they come.

The way I am doing that is create an Excel file with two columns named source and dest.

The source column has the path of the URL in the old Joomla site. For example, if the URL was https://www.example.com/foo/bar you must only put foo/bar into this column.

The dest column has the full URL of the new WordPress site.

Export this Excel file as a CSV file. Now you can import it via phpMyAdmin into the wp_admintools_redirects table. Ta-da! All your redirects are ready.

Note that I have done that a. going from one Joomla version to another (1.5 to 2.5, 2.5 to 3.2, 3.10 to 4.1 on our business site alone), b. going from Joomla! to WordPress (on my blog), and c. going from WordPress back to Joomla (again on my blog; the inevitability of the Block Editor in WordPress killed blogging on that platform for me).

Finally, let's talk about switching software :)

You can convert your Joomla! subscriptions to WordPress subscriptions at no additional cost. We actually allow our clients to convert from Joomla to WordPress and vice-versa once a year, at no cost, to make it easier for people to switch platforms. If you're interested, whenever you're interested, do let me know. I will switch your subscriptions over which means that you get access to Akeeba Backup for WordPress and Admin Tools for WordPress, simultaneously losing access to their Joomla! counterparts.

First of all, the data format is wrong. This is not a valid CSV file. CSV files use plain double quotes ("). Your file is using typographic quotes (“ and ”). Tell me you're using a Mac without telling me you're using a Mac (I was using a Mac from late 2010 to late 2023; I am not making fun of you). If you want to edit text files for computer consumption you have to use a real text editor, like Smultron.

The second problem is that your source column starts with /index.php/. Remove that. That's not part of the URL path Joomla reports.

To give you an idea, here's the first two lines of your file, as they should be:

"source","dest"
"people/appointments/appointments-articles/9698-new-head-of-international-development-appointed-at-bnp-paribas-leasing","https://www.assetfinanceconnect.com/new-head-of-international-development-appointed-at-bnp-paribas-leasing/"

Hello Edward,

I have converted your subscriptions as per our previous discussions.

Have a wonderful day!