The other item from the subway is the Black Bodice. From your map, I can see that you have found the Black Maxi and Iron Plate in the ER already. The switch to open the nurse's dungeon is currently accessible to you; it contains a Black Whip and an encounter that drops an extra 100 Rm (in addition to the standard enemy drops). Since you have also reached the surgery wing, a rare light weapon and accessory can be picked up fairly quickly after first entering, with a few more items found further in. The gated items near the hospital entrance cannot be collected yet. There are a couple other hidden items in the ER, but nothing important.
Before I go on, I am not trying to deny that you had a bad experience, but I do contest some of your specifics, and this in turn leaves me unsure of what needs tuning.
I am not really concerned about players choosing to grind when/if they find it necessary, this is part of the reason there are random encounters in the first place; however, I disagree that the pace of acquiring upgrades can be pegged solely to the pace of grinding the weakest enemies for currency, because this is not the only source of either currency or equipment. The player is also not expected to buy every upgrade before moving on to the next area (where there are more treasures to find and XP and Rm drop more rapidly), or even to buy everything at all, since the best equipment is unique and found in the dungeon. If the player does choose to grind, even just reaching the next experience level will itself reduce the difficulty long before grinding enough money to buy everything.
This is also why I have a disconnect with the characterization that the game is unnecessarily padded with grinding. This implies that progression is simply (and deliberately) not possible without taking considerable time to do nothing but fight random encounters, and I don't consider that accurate. The enemies in each area are balanced around the assumption that the player did little if any grinding to get through the previous one; I played through these maps one by one, without grinding, and scaled the next map to match how strong I had gotten naturally by that point. I cannot see this approach as padding. My initial (and honestly most) balancing was done with the default party, but the difficulty curve has held generally true for every party build I have played so far, including one with no healer (ironically my fastest run).
I recognize that knowing the game inside and out allows me to complete it much faster and easier than someone unfamiliar with it, but if the game is padded with grinding, then I myself would not be able to complete it without significant time spent grinding, any more than anyone else would, because the math just wouldn't allow it. Moreover, the fact that I know exactly how to advance means that my balancing is based on fighting even fewer encounters (and thus earning less XP/Rm) than an unfamiliar player would.
This is the problem: I can't reduce the grind because I didn't add any and don't see any to reduce. Just increasing the amount of Rm dropped from enemies does not, from my perspective, really make sense to do, since I don't feel it would really materially address your complaints. There are things that I can consider doing to make the early game more forgiving, some of which we have discussed already. The cost of healing and wipe recovery is something else I'm willing to look at it. However, when you describe your experience as being insanely difficult and frustrating to the point that you struggle to progress any further, it is difficult for me to match this to the text of your feedback and thus assess the root of it. I will take a look at your stream and see what I can observe.