You can also try and make your own acapellas. If you have both the vocal and instrumental version of a track, you can use the "phase inverting" method, it's long and meticulous but turned out to be pretty efficient for me

Here's a video on how to do it in Ableton

https://www.youtube.com/watch?v=FeYZ5-d-TxE

Definitely do the "phase inverse" method if all else fails,

Tutorial in Audacity: https://www.youtube.com/watch?v=_p5QC-4jGWA

Maximus -> FabFilter Pro-Q to cut the Side at around 200Hz -> Ozone 5 to Dither and Intersample detection. that's all

Always separate production from composition, it'll make your life easier and you'll be more motivated to do both. you won't be motivated if you have to think too deeply just to create a mix/song.

If you got cool melodies, write them down or just record them on your phone as an audio note. you'll be back to them later when you need ideas.

For production, just screw around with tools and create presets that you'll  find useful, when you'll be working on a song again you have something to use without thinking too much ahead.

And organize your DAW if you aren't planning to do music at all. bottom line, always do something with your DAW even when you don't have a full project.

Came here to recommend a cool plugin for those who want to look for a nice alternative way to pitch shift vocals/samples in real time as well as vocoding for example.

http://polyversemusic.com/i-wish/

The way it works is that it freezes cycles of audio in real time as you output MIDI to it, there's also options for formant shifting and LFO assigning, cool stuff. all for a whopping 99 bucksssss

Some examples that I created in a short time: