I really hate to say this because TeoreX has been been great and a long time contributor to GOTD, but most things AI related tend to get expensive -- the press talks about Open AI (Chat GPT) possibly going bankrupt -- and smaller companies, without the billions of dollars Microsoft or Google etc. have to spend get left behind. PhotoScissors doesn't claim to use full-on AI -- only "deep neural networks" -- but it's close enough that it requires their servers to handle the processing load, so they can only afford a 6 month, 100 image extended trial. The big guys let you do background removal &/or replacement for free, along with editing, layout, & image generation...
adobe[.]com/express/feature/image/remove-background
create.microsoft[.]com/en-us/image-background-remover
canva[.]com/learn/background-remover/
That said, automatic background removal &/or replacement should not always be your 1st choice, especially if you're after higher quality results. If you want to change a specific part of a photo [edit, remove, replace etc.] the 1st step is always selecting that part of the photo, defining the boundaries of exactly where that change will take place. AI still struggles with that. If you zoom in and look closely at the photos on say a major news site, you'll often see everything in the photo has crisp, clear edges -- unless you've got Very expensive camera gear, your photos are not very likely to be so sharp. And then you've got things like foliage and hair, where a hair or a leaf's edge happens to be in the middle of a pixel, which is the smallest thing you can select. In Photoshop AI pretty much just gets you close, saving time. Then there's a 2nd step, also using AI, to help refine the edges. *Then* you get to work manually fixing any areas that the 1st two steps didn't get quite right. Long story short, if quality matters -- if you're not just doing a quick, fun snapshot, like hey, I'm at the beach sort of thing -- you're better off using something like Franzis Cutout if you don't want to pay for and learn Photoshop.
Now, once you've got a really good selection, AI can *sometimes* help quite a bit with a replacement background, but currently you'll likely find that in this respect AI is still very much a work in progress, so your results will vary depending on your perseverance & how much luck you can summon. If you want to make a background replacement look convincing you have to match the lighting / shadows, the colors, even the sharpness, and AI can do that [if/when it cooperates].
One thing that can help is to get the edges in your photo as clean as possible beforehand, which helps selecting whatever objects you want to keep or replace. There are a ton of things that can make a photo not sharp -- try to figure out what if anything is hurting your photo so you can [hopefully] take steps to improve it. If the camera or subject moved, so you have motion blur, usually it's a lost cause, but most everything else can be improved with [sometimes lots of] work and the right tools. Lot of times it's unfortunately trial & error, but once you do figure it out, chances are that solution will work the same for every similar photo, for example I'm working on a ton of digitized photo prints, and 99% of them all require the same things editing.