I don’t get why you would spend that kind of money for only a “share” of art. I’d want my own painting for that pricetag.
Investing in art is almost always a big mistake. Most art dealers are criminals of some sort.
I’ve watched too many cheat people out of money. One great scheme is to take a work on consignment, then sell it and “forget” to tell the customer. Often they will lie and say it hasn’t sold.
If you want art, buy stuff you like and don’t worry about the value. I’ve done well buying from young artists at art fairs and small galleries. The stuff on my walls is pleasing and a few pieces have significantly appreciated in value.