dont even think about buying a decent printer yourself!
considering the amount youll actually print where that quality is needed, the cost of paper and inks (pigmented are the ones to go for if you want to have them lightfast and in museum quality), the cost of the machine itself, and the amount of time invested in keeping them operating properly (nozzels are tiny compared to literal rocks of pigment). theres not much room for a worse choice than that. i made it myself and its just 1 of 2 investments i really regret yet.
have it done by a professional company. go there and recheck it yourself on a calibrated screen of theirs. this should provide you with a good representation of what is to be expected. you can aswell have test prints and recheck them in comparisson to what you see on your screen under a given lighting, yet the visit at their office is most likely the cheaper and more reliable alternative on the long run.
"Have only 4 values, but all the edges you want."
"To any man who has slaved to acquire skill in his art, it is most irritating to have his ability referred to as a 'gift.'"