There are going to be more items. I think a full set will be around 200? Maybe more, maybe less. It's very doable to get everything. Maxing out does make it so you can get dupes for items you like. I personally don't know what the items are, nor am I that interested in what I have seen so far. I just think decorating a room following themes is fun ^-^
I also have a second character, so not maxing out won't be a problem for me anyway. The heart crystals are really pretty though and I kind of wanna get a bunch to trash my island with