Basically any Kubota tractor will meet your specifications, it comes down to how much you want to spend, and how fast you want to work.
In that situation, I tend to fall back on rules of thumb. BX for 0.5-3 acres, and if your primary task is mowing with a bit of tractor work. B2601 from 1-5 acres, more of a balance between mowing and tractor work. LX 3-10 acres, mowing no longer the focus, but perhaps snow work or you want a cab. L for anything 3 acres and up where you don't mow.
Arguably you could be B, LX or L, depending on what duties you want beyond loader work. If it's only loader work, the L is most capable, but any of the three will do the job. BX will strictly do the job, but has a bit less ground clearance and a bit less capability - I wouldn't go there unless you specifically want to mow and/or want a tractor that your significant other will believe is really just a lawnmower with a loader on it (they're more capable than that, but your significant other will believe you).
If you'll drive the tractor into the unmanaged portion of your 3 acres - to deal with tree fall, mow trails, or just general property maintenance (perhaps getting to fence lines or tidying creeks or whatever), then you'll probably want a bigger machine than a BX, just for ground clearance and because the bigger wheels make you less likely to get stuck.