If you are trying to save money, you can get a perfectly fine shelf from IKEA or Amazon (or I'm sure elsewhere) for much less money. I know you mentioned you are fine spending money for quality items, personally I think I spent like $60 on a shelf and splurged more on quality toys. Totally up to you of course, just a thought.

I'd also recommend checking out Etsy for toys and activities. I got some really nice kits for 0-3 months, 3-6 months, etc. HeirloomkidsUSA has good quality toys in bundles like that.

I'd get some woven baskets and wooden trays to place activities in and on.

I'd also recommend a mirror (shatterproof) at your baby's level and adjust as needed. We had this pull up bar and mirror set which was great because it grew with him. First as a mirror low to the ground, then he started using the pull up bar and now we just use the mirrors over his toy shelf (he's 19 months).