I have a question and wanted to see who can help or guide.

I have a switch I bought day one. I finally bought an SD card but not a nintendo branded one or a name brand one like sandisk. It is a 400GB one that I got off of Amazon. Now I formated the SD card and it reads fine. I downloaded one game on it and it worked fine (Wareface). Now when I try to download another one (Wareframe) it downloads to 99 percent but then tells me Error Code: 2005-0003. Then I try to redownload it again and wont't even start downloading at all. It just gives me error again Code: 2005-0003 right away. I take out the SD card and reboot the console. Once I do that the next game I want to download starts to download fine until again gets to 99 percent. Then gives me again error code Error Code: 2005-0003. Now I was able to download fortnite completely but when you trey to play it say file is corrupt. You go to data manage to find corrupt file for the game and it say you need to redownload it again. 

Now if you reformat the SD card and download any game it works fine. Then once you do another game back to square one where it does not allow a second game to download. So I am at a loss and not sure what to do or what is wrong? Is it my console or SD card from my issue. Thanks for any help!!!

Try a different SD card and see if it does the same thing or not. Even if just a 2GB card or something. A game like Lightening force is cheap and under 50MB so could be a good test game. Also, try downloading the game to the system's memory and see how that goes. Sounding tho like a bad SD card. Prob should go with Sandisk. Nintendo branded ones are just overpriced and I think they are Sandisk with a Nintendo logo premium price hike. Nintendo did that in the Wii era as well.

what if you start multiple downloads at the same time?

Sounds like a bad SD card to me, this is a useful tool for checking:

https://3ds.hacks.guide/h2testw-(windows).html

Some amazon Sd cards are low storage relabeled as higher storage. The comments are filled with such issues. As a rule I purchase them instore only.

There are these fake SD cards with ridiculously low prices available online. Somehow or another, they lie to you device about how much space they actually have or even how fast they are. They'll say 1tb for $10 or something crazy like that. I feel like you may have been taken by one of these scams.

This is the one I bought and the more I gratefully get your input I think I got snookered
https://www.amazon.com/gp/aw/d/B08F3CP8Z8?psc=1&ref=ppx_pop_mob_b_asin_title#aw-udpv3-customer-reviews_feature_div

Yeah, that one is a no no. It's got to be either SanDisk, Samsung, Kingston, PNY or Lexar. 

Looked at the reviews. Seems it's only 32gb. Those cards fool people because they kinda work but when they get full they overwrite the old data. Most people use them on their phones and never realize their old pictures etc. aren't there anymore. Because you used it on your Switch, you found out instantly.

Yeah, return it if you can and wait for Black Friday/Cyber Monday and get a SanDisk 400GB card.