The tablet is a good in between device. It is bigger than a smartphone, and smaller, and more handleable than a computer. However, if you can not afford a tablet, this is not a requisite. Tablets can be pricey for the role they serve. With that in mind, that is something you would want to weigh carefully. If you decide to get a tablet, I would recommend that you get one with a cellular capable option. Also, get a tablet that matches your phone’s OS. If you have an iPhone, then strongly consider an iPad (any variation). If you have an Android phone, and while it will be harder – get an Android tablet. The learning curve will be less, and you should be able to use purchased apps on both devices.
Depending on the cost of what you would pay for both an Android phone, and an Android tablet, you might be better off with a book style folding phone. When closed, it is the dimensions of a phone. When open, it is closely related to a small tablet. There are two different types of book style foldables. The first is a passport book shape which I will get if I had to get one, and then the elongated type which you find in earlier version os Samsung foldable phones, and the current “Ultra”. If you have to buy both items, then the Samsung Galaxy Fold 8 is about $2,000 for the minimum version. This is definitely a hit, and you may not have such financial resources unless you just been approved and received your lump sum check.