Your decision is influenced by the height of the mattress and frame when placed together, along with how much of the headboard you want covered by the mattress

Slat height is 12.75 plus mattress of 13.5 is 26.25 for the Heatherfield. I think this is fine. I am told that I can consider a frame that calls for a box spring, but use the bunkie board. In that case some of my mattress will be recessed. Is that an issue functionally? Thank you!

Look for a platform without a recess. Your mattress doesn't need springs. It's complete in the comfort it provides. So, drop that out of the requirements. I'd determine the finished height I wanted as my primary requirement. Ease of making the bed would be second. Looks third. A sideboard look isn't on the list.

I found it odd that a platform bed in itself would have a mattress that drops in 5" to the slats. Debating if that would be an issue making the bed.

Let's just say it would be a big issue, buy band aids

TUFJORD Upholstered bed frame, Gunnared blue, Queen - IKEA

This shows an option where your mattress is not recessed.

Thank you! I will check IKEA.

Heatherfield Bed from Anthropologie

I don't see any problem. You would not want anything under the mattress to lift it. The mattress fitting into the frame is part of the look. If you lifted it 5 inches so the bottom of the mattress was even with the top of the frame it would look very wrong. Of course you would need to lift the mattress to tuck the sheets, blankets, even the bedspread under.

The type of platform bed where the mattress just sits on a flat surface is a very different look, the bedspread would probably be left to hang over on all sides. This picture I posted I understand to be the bed you are considering, where the mattress goes into the frame 5 inches.

I wouldn't mind an inch or two of recess (just realized that my upholstered bed frame has exactly that) and I think it provides a nice clean look if the bottom of your mattress is not sitting above the frame, but 5 inches seems way too much and will be terribly inconvenient for making the bed.

I am not a fan of rolling into the bedframe. If knocking up against it when trying to make the bed. Of rolling into the frame or over the frame when getting in and out of bed. Lived this when we were first married and DH came with an old style water bed. Learned to manage until. Try it when you are 8mos. pregnant. It was a no go. That's one obstacle/barrier that just should not be.

A platform bed is made to not have a box spring and I have no idea why anyone needs a 13.5 thick mattress . I have never owned a box spring and have never had a 13.5" think mattress my mattress right now is 10" thick and more than enough as for how it sits in the frame I think it is about 3" into the frame our bed has a rim all around 3 sides that is about 3" wide we have a memory foam mattress . we are in our 70s and do not find this set up to be hard to get in and out .

We didn't "need" a 13.5" mattress, but ended up picking a Beauryrest Black Hybrid mattress that we love. Best mattress we've ever owned. Trying now to select the right bed frame. It's tricky due to the mattress thickness.