I forget which one it is, but you can try to hold R while trying to launch another game to open the HBmenu or just open the gallery normally and it'll open HBmenu but I think that would still be in applet mode.
You should try this. It's not guaranteed to work, but still worth a shot.
https://gbatemp.net/threads/cleaning-up-nand-to-play-online-safely.551767/
After doing that, I played Fortnite since it was free and online to see if I would get banned. I did this around March 2020 and haven't been...
Sometimes the card isn't making good contact with the pins on the 3DS. Try putting tape on the back on the R4 (where the sticker is) to make it thicker so it'll push against the back into the card reader contacts. I had to do this on my M3i Zero to make contact with my DSi
Alternatively, you can install over the network using FBI and Boop (not Boop 2, that gave me errors but you can try it). It's slower than what @fmkid but it solves your problem of not copying the file onto the SD card.
https://gbatemp.net/threads/release-fbi-open-source-cia-installer.386433/...
I may try the new ram site, and download more RAM to my Switch. Not sure if ddr3 is the right ram
for it tho. Edit- no it uses floppy Ram, just like @AncientBoi