Well, the answer to your question is going to differ depending on which game/gen you want to clone on.
If you need cloning services in Gen 6-7, then it's relatively easy to clone 20 times. There are multiple methods to achieve that end, which take a varying amount of time. Nothing special other than a card reader is needed, and a number of people can help you. If you need help cloning in Gen 6-7, send me a msg and I can help you.
If you're looking to clone in SwSh, it's going to be a lot more difficult. First, you have to keep in mind that cloning is semi-locked due to Home - any Pokemon that has been to Home has a unique identifier tag that registers them. If Home detects two or more Pokemon with the same tag, it will delete them (thus rendering cloning moot in such instances). If your mons have never been to Home, then this is not going to be an issue.
However, there are also currently no external methods to clone in SwSh. Unlike prior generations, Pokemon saves in Gen 8 are stored locally rather than on the cart - which means external devices can't read the data. However, cloning is still possible
if you can install CFW on your Switch. This is a lengthy process which not many people are able to or are willing to do. Other than figuring out that for yourself, the only active service is Anubot on the Smogon Wi-Fi Discord. I do not know any further details (I am not on Gen 8) so I would recommend asking on the discord server
here. That service may or may not be able to clone in the volume you are seeking.
If BDSP is the game you need to clone on, you're in a tougher spot. Currently, there are no tools that have been developed (it's only been out for so long) to enable direct cloning. A cloning glitch was discovered for BDSP (you can read up on it
here), however, it has since been patched. If you have updated to the latest version for BDSP, you're going to be out of luck until such tools are developed - if ever.
Hope this helps you!
been looking for days with no luck 
