A tripod for indoor, macro photography...
So, first up, let's dispel the myth of the center column adding instability. A center column, lifted to it's maximum height, creates a precarious platform for the camera to rest on. At that point, you're essentially balancing the camera on a stick and there's not a ton of inherent rigidity to counteract vibrations. But...you're going to be inside. You can use mirror lock up and you don't have to worry about wind causing vibration. So, even in the most precarious position imaginable, you'd still have a stable rig.
Now for some center column benefits: Find a tripod that allows you to pull the center column out and put it back parallel to the ground and upside down as well. Why? For flexibility! You never know when you'll need to shoot straight down on something or maneuver the camera to a wonky angle. Additionally, you're shooting macro - the smallest movements make a world of difference. Got the whole rig set up but need to move the camera up 1/2"? That can be a royal pain without a center column.
While we're talking about micro movements and royal pains, let's jam on tripod heads. Research "Geared tripod head." You may not need it for your macro work, but having minute movements available to you is very helpful.
Now, what about the tripod as a whole? The tripod needs to be able to support the weight of your rig, and will only get more stable and sturdy as you find one that can support more weight. Because you won't be traveling with it, you can save some coin here. Look for sturdy aluminum tripods. They don't have to fold up small and can weigh as much as it takes.
TL;DR - get a sturdy aluminum tripod that can handle a good deal of weight and save some cash here. Do get a center column. Use the saved money on a good geared head. You won't be getting out of this purchase at under $300.
Nobody likes to spend a ton of money on tripods. But, consider this: You've just spent over $2k on a camera and lens set up and peripherals and you absolutely cannot take your shot without a tripod. The difference is in getting the shot, or not getting it. What's that worth to you?