Basically, I’d like to delete tattoos or somehow blend the area to match the uninked skin nearby, and also to cartoonify (preferrd) or blur faces. If there’s a free/simple app where I could just select and click a button that would be great, but if not if someone could tell me or link me to a guide on how to do that I’d appreciate it.
Single click isn’t a thing for this. You can do the tattoo thing n Photoshop with the healing brush and clone tools, or like frequency separation if you want to be fancy, and the face thing with the blur or mosaic filters also in Photoshop. Lightroom can do a jankier version, and you can probably also do it with the Gimp but you’ll hate yourself the whole time because that’s what the Gimp does.
You can do the blur face thing with free mobile tools like VSCO, but IDK of any mobile or free apps that reliably make tattoos invisible.
Side note… almost any app is going to sacrifice the privacy of your original image to The Cloud. If you don’t mind that and you legit sub to CC Photoshop, you can get the Ps betas and use their Firefly generative engine for AI infilling.
Staying with foss, there is a GIMP plugin for Stable Diffusion on StableHorde (a crowdsourced distributed network).