Her office setup is not on the back porch. Where people are getting the, "it can't be the basement; it must be the back porch" stuff, I don't know. The back porch doesn't have the shitty acoustical ceiling seen in her TikToks; none of the rooms on the main floor of that house do, and there is no upstairs. So she's not lying when she says it's in the basement.
Looking at the pics again, I'm also not seeing the third bedroom or second bathroom, so I assume those are also in the basement (lovely!), of which there are no photos (probably for good reason, as cheaply-added basement rooms are inevitably shit). The only access to the basement that's visible is the outside hatch on the west side of the house, but maybe there is a set of interior stairs that Juliana uses (because I don't see how she could bend over and lift the hatch doors without falling over, and down the steps).
The kitchen's noticeably narrower than the dining room, so maybe the basement stairs are on the other side of the interior kitchen wall. I can't figure out where the door is, however. (But damn, you can look straight into the bathroom from the dining room—that's great floor planning for you.)
That said, no, it still doesn't make any sense how the basement is any more accessible for Juliana than the rest of the house. But, then again, nothing about their living in this particular house makes any sense at all. So I suspect she's been put down there by Corissa, so Corissa can lounge in bed at whim, and her house-elf sister (and her man) can have a main-floor bedroom.
And it's possible that Juliana has recovered just enough mobility to make it up and down the porch steps and the basement steps, but she's milking her shitty situation for any sympathy she can get.
(Also, the wood floors in that house look like even worse hot garbage than I remembered, and I would have had them stripped, sanded, and refinished before even moving in.)