If I want to erase the white around an object

Funny, this is literally one of the primary examples of something that GIMP did better than Photoshop (at least back when I was actively using GIMP a lot). GIMP has the "color-to-alpha" tool that allows for backgrounds to be faded into transparency (including converting the border of that object into translucent pixels that don't have the hint of the old background), which I remember being the easiest way to remove sky or other background from an object, and to place that object into a new background or other image.

I'm guessing that in the 10 years since, Photoshop has a bunch of those AI tools that can do that specific function almost automatically. But GIMP does do that specific task pretty well.

Yes. A lot of that is going on with instances being blocked en masse for allowing too many spam/bot accounts without any corresponding high quality activity coming from users registered with that instance. It's very much in flux right now, with instance administrators trying to figure out which metrics to use and what lists to trust, but I imagine a more mature/robust process will be used by most serious instances soon enough.

I mean honestly, people keep talking about apps for accessing kbin/Lemmy, but I'm not in any hurry. The browser interface works fine on both desktop and mobile, so I don't need an app.