You'll have to think outside the Home app. Just a warning, it's a rabbit hole:

I currently use Sharptools to design dashboard layouts using FullyKiosk (a speacialty browser app that costs ~$10 for full features like motion detection - so the tablet only turns on when you walk by), and tap into my smartthings account to pull all of my switches, sensors, etc. You can tap into various other smarthome services, too, like Hubitat and Home Assistant.

Then you've got to find a way to mount it. I use a 3D printed frame and USB charging line from Makesbymike (they make frames for various tablets, and offer various charging solutions), and then a recessed outlet box and outlet that the tablet/frame sits over (which requires some DIY 120V wiring and outlet installation).

Here's an image of my master bedroom dashboard. There's all sorts of things you can add via sharptools - calendars (that tap into your Google or Outlook calendar), weather widgets, light/device status and on/off capabilities, video feeds (the missing image is a feed from my driveway); the possibilities are endless, but they do have a subscription service if you want multiple dashboards ($30/yr, but you can get 20% off through this link that gets me 20% off too :) ). The developers are great and are very helpful in their forum (https://community.sharptools.io/). They work on all sorts of things and then you basically copy paste some code, or they'll help you work through any custom coding you want to do to build your dashboard. I'm using the weather tile one of the developers came up with.

One limiting factor is the tablet - Amazon has recently been using updates to prevent you from circumventing their ads, making it harder to do all of this. The "hack" is through Fire Toolbox (here), but I found it didn't work very well on a 2021 10HD tablet that I accidentally updated when I got it set up. The ads kept force-closing the fullykiosk app. I wound up buying a refurbished 7th gen Fire tablet and everything went smoothly after that.

For any given setup:

1) Fire tablet - currently $40-75 on sale, but beware of problems with the current OS

2) Walk mount and charger - $50-60

3) Recessed box and outlet - $35 + 120V wiring, etc.

4) Sharptools subscription - $30

5) FullyKiosk app - $10

What most people do is install a recessed gang box like this one, typically running 120V from a switch box. (I've got all of mine 1-2 feet above switch boxes) Use an outlet with USB ports like this one. Then mount the Makes by Mike frame right over the gang box you installed, routing the "USB Direct" adapter behind the tablet, through a hole provided in their frame backing, to the USB port.

Based on what you've said, I think you're wanting the "5v DC Direct" version, though that wall wart is going to be tough to 1) fit in a recessed box and 2) fit behind a wall-mounted tablet...thus why most do the USB outlet and USB direct adapter.