Raised beds are in ground. Raised beds are called "raised" because You double dig them (loosening compacted soil) and add organic matter to the soil- hence raising the soil level several inches.

Add large amounts of leaves or other organic matter after harvest and let sit until planting time.

Don't tell the new potatoes that they're growing in a previous potato location. Sssshhhhh!
I grow my potatoes in a raised bed about 6 feet square.
Do it every year.
After this season's harvest, I added some soil amendments (manure and organic materials like compost) and some 10-10-10 fertilizer and then leveled the soil. Had some rain recently and that has compacted the soil nicely. Might plant some onion sets there later in the Fall for harvest in late Winter/early Spring. And might fill in the bed with a Winter cover crop like rye or clover or vetch or fava beans. Come February, I'll put in new potato seed as soon as it is available at my local nursery.
Those of us with limited space are best served by soil rejuvenation in my opinion. My baking potatoes this year were excellent and the fingerlings? Yum, slice thinly, apply olive oil and roast them with garlic salt and fresh basil.

The biggest risk is associated with diseases. For instance, this year many of us have had entire crops of potatoes and tomatoes wiped out by late blight. Any chance of me growing my tomatoes or potatoes within 25 feet of where they were this year? NO WAY!

In other words, really depends on your location, your history and your tolerance for risk.

As noted, the primary concern is disease. Some diseases will survive in the soil over the winter, so if you had any of these soil borne diseases this year, they would be present and more likely to cause problems next year. Planting certified seed potatoes each year and avoiding getting any disease through the air/wind/rain, you can grow them in the same spot for years. Some of these diseases will only survive on host plants (typically all members of the nightshade family including tomatoes and peppers) or their residue, also. Removing the dead vines in the fall will help reduce your disease risk the following year.

Over time, the potatoes will tend to suck out the nutrients they like most if you don't supplement. Adding some rotted manure or compost to the patch each year can offset this and all growing potatoes there indefinitely.

If you eventually due get infected with soil borne diseases, chemical treatment usually isn't practical for a home gardener because the treatments require special handling and are generally sold only in commercial quantities. At the same time, soil conditions can promote or retard these diseases, so if something appears, identify it, then check its preferred soil conditions. Raising or lowering the soil pH a little may be all it takes to keep it under control, and a lot of disease issues are related to the weather conditions of that particular year and a problem one year may not get the right conditions to be a problem the next.

IME, the disease issue for potatoes on a garden scale in a highly mixed garden are much overblown. And it stands to reason that the chance of infection is less likely if one saves one's own seed. By saving my own tomato seed I escaped the late blight this year, for example.