Ikea Eket shelves with a large vinyl collection?

It's too bad they stopped making the Expedit line.  The Kallax, which  replaced the Expedit, is basically the same as the Expedit but thinner and weaker.  That was the whole point of the Kallax.  They wanted to reduce cost/use less wood.  When I put my Expedits together, I glued every piece together with construction adhesive and then carefully leveled it.  It's extremely solid now.  You could probably do this with any of their stuff to increase the strength.
https://gizmodo.com/heres-why-ikea-is-discontinuing-everyones-favorite-sh-1527126312

Quite right, Elizabeth. When I checked out the EKET and the Kallax at my IKEA, I saw the EKET had a back panel, the Kallax not. I pushed on the side of a 16-cube (4 X 4) Kallax, and it moved---a lot. When I assembled my EKET's, they "gave" a little when pushed (not nearly as much as the kallax), but were very structurally stiff after the back panel was slid into place. It locked the whole structure together.

Fwiw, I decided on the Kalax, 2 units of 4 cubes, stacked and connected via barrel bolts. I could not be happier with them and plan on adding a backing panel for additional stiffness.  But that has time and is not a priority. I did add some felt pads to the bottom unit to facilitate ease of moving as required from time to time.

I have to admit I never even gave Ikea a thought for record storage.
I got my shelves from Amazon, will have to see who they were made by, but each unit consists of a 4 compartment cube at approx $60. No back but the outer wood is an inch and half thick so it ain't moving! The no back annoyed me for albums going too far back so I just added some flat wood " bars" to the backs( 2 on each shelf) which stopped them all in same depth. I feel the house will fall down before these will.