I kinda do that with Samsung DeX. You plug it into a USB-C dock and it basically turns the phone into a computer. With Android apps running in little windows (not MS windows). It's amazingly useful, it's a bit like Microsoft's old convergence idea but it actually works.
I use it at work when I forgot to put my laptop in my bag (at home it's hidden in a dock behind my screen so it happens from time to time). I can work a whole day with meetings, doing some MS Office work etc. And if I need real Windows I can connect to a VDI. I could technically work like that every time I go to the office, the only reason I don't is some AD admin work that is not allowed in a VDI. It works technically but it's an internal rule thing.
I also use it on the go with an Xreal Air and a foldable keyboard. I have a whole computer with me for the weight and bulk of less than an iPad Apple could easily do similar, however their do really thrive by selling as many devices as possible so I doubt they would do it.