The thing to remember is that there are two types of fryer. The bucket/drawer ones and the mini oven/shelf ones.
Both do essentially the same thing, which is by no means always frying, but which one to get depends on what you will cook in it most.
The bucket/pot/drawer ones are ideal for chips and similar. You can cook many other things in them, but you need to have tins and pots to fit inside them, which is limiting. They can be difficult to get things in and out of when hot. I have a Ninja Foodi 14 in 1, which I thought was going to change my life, but I find it awkward to use as the pot is large and the things is heavy. There are much less fancy ones out there, but the pot problem remains. My least favourite thing about it is that whereas you can cook (eg) a lasagne in it, you then have to either serve it straight to the plate or find a way to put the finished meal into a serving dish, as only very small ones will fit inside, and even then you will struggle to get them out of a hot pot. Living alone will make this less of a problem, though.
The other kind are the mini oven ones. I have one of those too, and much prefer it. It has shelves, so you can easily cook three things at once (eg chicken, roast potatoes and yorkshire puddings) and you just open the door to get them out. There is a bit of juggling of the shelves needed, whereas you shake the food in the pot ones. If you take the shelves out, the cavity is big enough to put a casserole dish, cake tin or (small) yorkshire pudding tray in, so IMO it is a lot more versatile than the Foodi, which markets as being able to do it all. I have make cakes, yorkshires, casseroles, puddings - all sorts of things in the oven one, and whilst I force myself to use the Ninja (it is at home but the Tower one is at the caravan) I don't find it anywhere near as easy. I am 62, and have no physical limitations.
Both save money on fuel, though.