Growth hormone is the absolute GOAT and it's the number one peptide option. I would go to 2 to 3 IU's per day. Start there and then you can work your way up.
I wouldn't listen to some YouTuber on how to use steroids. The problem with YouTube is that they will take down any video with useful information, especially when it's a video and not just audio.
I think the best thing to use solo is going to be testosterone. That is the GOAT but it doesn't mean you can't use other things solo as well. There are other options you can go with.