Is the free tier using the v3.5 model? If so then honestly it's way behind v5 - I remember at the time getting some OK stuff out of v3.5, but honestly even v4 is a massive upgrade and v4.5 and v5 are way better. v3.5 does not do justice to what Suno can do nowadays.
As far as uploading copyrighted stuff, yeah it is very random. I was able to upload most of Clayman, for example, but OFTW was blocked. Most of Battles was blocked but I could upload Siren Charms stuff... so honestly I have no idea what the mechanism is. I was able to upload the theme song to "The Bill" (classic 80s/90s British drama), but the Quantum Leap theme was a no go.
There is a way around it - basically just slightly speed up or slow down the song in something like Audacity. You can readjust the speed in Suno if needed, but if it's only a very minor correction it may not matter much if you're doing a cover.
In terms of lyrics, it doesn't scan for them when uploaded, but if you write the lyrics as part of the cover it will sometimes strike them out - so yeah, at the point of creating the cover it does recognise some lyrics as copyrighted. Again, very random though. I uploaded the Chip 'n Dale Rescue Rangers theme and whilst it let me upload the song, somehow the lyrics were copyrighted, lol. There's a very easy way around that, though - just amend the spelling. Change "like" to "lyke" or "hey" to "hay" and presto, you're all good. Not exactly a robust system.
All worth it to get sick metal covers of the likes of
Captain Planet (ngl this is actually pretty awesome, lmao
)
Quantum Leap
The Bill
Chip 'n Dale Rescue Rangers
Jayce and the Wheeled Warriors
Sonic 2 Ending
Just proof that metal makes pretty much anything awesome
