We are going to need more people mixing songs so we can work through all the submitted vocals in time for the deadline, so I've prepared a resource of torrents for plugins you can use to help you get started with mixing your vocals and stuff later on, I pulled all of them from RuTracker: https://files.catbox.moe/ev15il.zip
Use Qbittorrent to get the torrents to download. Torrents are basically download links, so just having the "torrent file" won't give you the plugins.

For audio software, I recommend REAPER. It's not as easy as Audacity, but once you learn it you'll be able to do whatever you need: https://www.reaper.fm/download.php
Recommend looking up some guides for getting started with mixing, but worst case you can ask in the thread.
We have a mixing template for it, included in the torrent ZIP.

In case you have a powerful enough PC, this is what you can use to remove vocals from songs you've downloaded: https://github.com/Anjok07/ultimatevocalremovergui <--- USE THIS FOR INSTRUMENTALS

In case you need high quality files for songs you like, the best bet is to find them using Soulseek: https://www.slsknet.org/news/node/1

And finally, in case your music only exists in the form of a Youtube video, here is YT-DLP. It's CLI, but it works well enough if you remember to use "yt-dlp -x ": https://github.com/yt-dlp/yt-dlp
YT-DLP has a few GUI implementations, such as TarTube: https://tartube.sourceforge.io/