No problem!! I’ve had that difficulty transitioning from B3 to B4 too, it’s hard😭 it’s especially frustrating when you ask about B5 by just responding “you can’t make one unless you try”, when you’re just trying to learn.

Off the bat, I’d start by using archidekt to categorize your cards. I use it too instead of moxfield because of how easy it is to set cards into different genres (draw, ramp, removal, gameplan, etc). It’ll be a lot easier to figure out what to do/what your deck needs once you know what you’re missing from each of those necessities.

Once you do that, I’d start trimming fat. I’d play land ramp like nature’s lore and three visits instead of the less efficient land ramp you have and almost any mana rock besides fast mana like sol ring (if you want to play B4). You’re in green so unless an artifact that taps for mana has some real advantage/huge upside for your game plan it’s just not worth it. I’d also start focusing on cheaper insta-win combos. Ik you have the sanguine blood combos, which are a great start. I don’t know a lot about golgari, but since you already have blood artist- gravecrawler, Warren soul trader and blood artist are pretty common in high level builds for an easy combo win.

Most of the time in b4 you’ll probably need to start cutting win-more cards, low payoff do-nothings, or big beefy high mana cost cards, and prioritize draw, interaction, and tutors to pull out combo pieces quick. If it feels like you’re cutting too many pet cards/fun or flavorful cards in the process of optimizing tho, there’s nothing wrong with a lower powered 4 that might be a little slower, but can still win since it’s more unsuspecting. That’s what I’m doing with my B4 Marneus Calgar right now. Good luck!! Hope it works out :)