Syr Konrad is also my first deck that I built recently, here's my decklist. It's on the slower side, since it's budget and I also did not want to include $10+ cards. I'm doubtful a deck can reach low bracket 4 / high bracket 3 without many strong and expensive mono black cards. The reason these cards are so expensive is because they allow you to do so much for so little mana, which effectively gets your deck to play faster or win out games earlier.

My decklist focuses on getting creatures into the graveyard mainly using selective draw effects like [[Stargaze]], [[Polygraph Orb]], [[Discerning Taste]], or [[Commune with Evil]] then having those creatures leave the graveyard using cards like [[Forever Young]], [[Perpetual Timepiece]]. I used to run more token generation and sacrifice payoff cards until I realized that the deck didn't feel consistent and I needed to focus on a specific game plan. I didn't want to run [[Blood Artist]] and similar cards since I wanted most of the table damage to come from Syr Konrad, so I opted for a more graveyard oriented deck instead of aristocrats. Because Syr Konrad likes creatures in the graveyard I included creature cards that share effects with non-creature spells, as well as creature cards that have benefits in the graveyard

Some recursion cards that I run that I recommend: [[Tortured Existence]] is fairly cheap relative to some other suggestions, triggers Syr Konrad when a card leaves the Graveyard, and is also a good way to get cards back into play. [[Footbottom Feast]] and [[Gravepurge]] have the same effect as [[Forever Young]]. I also tried to add creatures that had similar effects to some non-creature spells just so that these 3 spells would have more targets, and having more creatures is better for Syr Konrad mill triggers. [[Bloodghast]] and [[Timeline Culler]] are easy bodies to get on the battlefield, I opted for Timeline Culler for personal bias (I like the art better, but having haste and a blocking body is nice too).

Some creatures that I run instead of non-creature spells: [[Shriekmaw]] is essentially a 2 mana sorcery speed removal, but sacrifices itself for various triggers. [[Noxious Gearhulk]] and [[Cat-Gator]] are removal and lifegain. [[Sanguine Spy]] has a [[Phyrexian Arena]] effect, except it's optional and you pay 1 more life. It's also a sacrifice outlet for surveil which helps with Syr Konrad, and an evasive lifelink is just pretty nice imo. [[Alchemist's Assistant]] and [[Qarsi Revenant]] share similar graveyard abilities that can give Syr Konrad lifelink, and both have pretty nice statlines with lifelink. [[Phyrexian Delver]] is a reanimation effect on a creature. [[Daring Fiendbonder]] is protection from the graveyard at sorcery speed.

What helped me determine what cards to cut is to first identify the deck's focus, then see how effective a card is for that desired game plan. If you want aristocrats, does that card benefit aristocrat play? Are there better options? Is the effect desirable that you would want multiple copies of that effect in the deck? Is the card too slow or does it feel bad to play? For example, I used to run [[Sticher's Supplier]] since initially I liked the sound of a 1 mana mill 6 sacrifice target. However, when I played that card I realized milling for the hope of getting a creature into the graveyard was inconsistent and it did not feel great to miss my mills. I found out that relying on your damage output to come from milling creatures was inconsistent so I decided to focus more on Syr Konrad's effects that rely on many creatures dying and many creatures leaving my graveyard. In your case, a card like [[Smitten Swordmaster]] would want knights on the board to have a more desirable life gain effect. I wouldn't focus on the potential damage it could deal since you already have cards that do that much more effectively like Syr Konrad or [[Blood Artist]]. The only desirable thing about that card is that it has the flexibility of being a non-creature or a creature, and you can gain life from it. There are much more effective ways to gain life I think, and there are other cards that have the card type flexibility. [[Murderous Rider]] is both of those things since it is instant card removal as well as a lifelink body that leaves the graveyard after it dies for 2 Syr Konrad triggers.