How to create a subdomain that minics SUB.domainDOTcom created by adding new website?

OK, I have 10 subdomains attached to 1459919.com which goes like this:
0.1459919.com
1.1459919.com
...
9.1459919.com.

Before I moved the sites from cpanel hosting to my own server running ISPconfig, I created using cPanel's Subdomains' function, which automated everything, including creating the needed subfolders on 1459919.com and proper pointing to them.
Anyway, a few days ago I moved this site 1459919.com to my own server running ISPconfig, and I wanted to reproduce what cPanel did without creating all 10 subdomain sites with ISPconfig's "Add new website" function but simply with its "Subdomain for website" function. To some extent, I have achieved what I wanted so to speak, but with some regret.
Take this subdomain http://1.1459919.com for example, most browsers will redirect it to the secure URL: https://1.1459919.com which I wanted. However, if I add some non-existing words at the end of the subdomain, I would normally expect to get a 404 error and then redirect that to my 404.php (to explain I did not migration everything over to the new server). Instead of getting a 404 error, the browsers simply stay at whatever I entered, for example, 1.1459919.com/non-existing, 1.1459919.com/non-existing.html, etc.
For the trunk website 1459919.com I use this setup:

For the subdomain setup, it is like this for 1.1459919.com according to what I searched and found on this forum...

So, is "L" the correct tag? Should I use R, No tag, or whatever for this purpose?
The reason, I did not use the "Add new website" to create any of these subdomains as stand alone website is because I do not want to end up of having 10 websites/FTPs to manage.

 

Any ideas or is it impossible to do it this way?
The regular way of creating the subdomain as new website is too much trouble just for this simple task.

 

OK, I am reading the ISPconfig manual and have learned about Vhost subdomain. Is this the right direction in my case? As long as I can use one FTP account to upload subdomain folders to /var/www/1459919.com/ then this could be a better choice. The problem is, I have already created the site in ISPconfig with this document root: /var/www/clients/client2/web12/

 

OK, I see two options: Aliasdomain (Vhost) and Subdomain (Vhost).
Cannot understand their differences.

 

OK, got it. Subdomain (Vhost) is what I need. Do not need to create a separate FTP account, as one is enough to access every folder related to a particular domain.