You might be able to use a joist hanger type thing. They're intended to work through a combination of through-bolting and bearing so that the wood would rest on a little ledge. This is a thing I've done in the past. It's pretty visible, but it'll hold the bed together. Home Depot carries things like this - by the hardware (nails/screws/etc). It's hard to tell what piece is broken, though.

If you brown the sausage and make the gravy in the same pan, you're going to get some brown fond mixing in with the gravy making it delicious and adding a brown color to the white milk, resulting in a beigey or gray gravy.

Considering that one of the mechanisms by which biscuits rise is through steam released from butter as it goes from very cold to very hot, I would think that biscuits should have butter in them.

https://basicswithbabish.co/basicsepisodes/biscuits-and-gravy - improved biscuits. If you have a food processor, use it to grate the frozen butter. Cold butter is key.

The capacity of a column is, in general, compared to the load on the column. The stress is equal to the load (P) divided by the cross-sectional area of the column (A) - P/A. For a 2x6 in compression, the cross-sectional area is the actual depth x width of the 2x6 (I think it's 1.5"x5.5", but it might be 1.5"x5.25" - been a while since I looked at a x6 member).

All materials have an allowable stress (S) in different modes of failure - bending, axial, etc. Timber has more failure modes than most materials because it behaves differently depending on how it's loaded (for example, compression perpendicular to the grain vs. compression parallel to the grain - the direction of the grain as compared to the direction of applied load plays a pretty big part in timber).

In the simplest terms, you want the allowable stress (S) to equal or exceed the applied stress, so S ≥ P/A.

If you drill a 4" hole in your 2x6, your width goes from 5.5" to 1.5", reducing the area significantly. And, if you reduce A, you increase P/A, pushing the load on the column closer to (or possibly exceeding) the capacity. That would be bad - don't do that.

There is more stuff that goes into timber design and column design, but this is the ELI5 version.