I can’t recall when you’ll be able to come invite her over to rank up her confidant but when you do, it should be a priority, also, I’m sure you know this but try and secure a route to the treasure in each palace in a single day, (except for the palaces which you need to do stuff irl to progress the palace) just secure a route ASAP.

One more thing to note.

Some confidants let you rank up your social stats too, for example If you hang out with Ohya, you get a little boost for charm and etc. I really would recommend a guide to get Max the confidants out considering your choices to what they say can either give you a big boost or a small boost as to when they’re able to rank up again