Arduino as switchboard w/bluetooth

First post, but I've had a hard time finding an answer searching. I'm looking to use my Arduino as a wireless "relay" by setting up some mosfets to control various accessories on my trail truck. Mostly various lights, but probably some other neat stuff, if I can get it to work like I want.

There are plenty of explanations on how people do that but what I want is to use the Android tablet that has my GPS on it to act as the switch. Also, a ton of that out there.

What I'm looking for help on is to find out if there is an app that would allow my switches to be displayed as a widget on the tablet home screen so that they are always there. I don't want to have to open an app to use the switches if that's at all possible. I've found a ton of apps that do what I want but don't have a widget

Not Arduino related, it's an Android question.

You can achieve this by using a kiosk mode app. I'm doing just that for a project of mine, an app called Fully Kiosk, allowing you to effectively set one app (the one that has these switches for your bluetooth thing) as home screen. Starting up your tablet will go to that app.

User has to enter a PIN code to get out of that one app. It's meant to lock down the device to a single app.

"I've found a ton of apps that do what I want but don't have a widget"

Can you give some details on what a "widget" is and how it would functions in your project/tablet?

Have you considered using an ESP8266 board (or ESP32) to control your accessories? They have WiFi and you could set it up as a server and then any smart-phone with a browser can display the control screen. There would be no need for a special smart-phone program.