You can use without port forwarding. Others without open ports won’t be able to upload to or download from you and give versa. There’s a sticky on the Reddit explaining this
If you can’t forward ports Soulseek will still work okay. Don’t let that stop you from joining
Private trackers really aren’t masters of op sec. They thrive through security through obscurity which the worst kind of “security”. And generally even fail at that (PTP, BTN, RED, OPS are so widely known)
That said I use them and I also don’t use a VPN so I just take that risk. It’s up to you
IP2 definitely sounds intriguing as truly (or close to) anonymous peer to peer