Your game must be bugged. There are usually 2 NPC clerks in the synthesis shop
Nah, the second NPC doesn't show up until you complete the "gather 5 quartz" quest in the level 2 forest. IIRC that's how I got her to appear, and once she shows up that's when you can see all of the quest-related synthesis options. It's a little finicky I think but after collecting all 5, and after watching that dude steal one and coming back to talk to Karen about it, sleep for a day and the 2nd synthesizer NPC should be there.
EDIT: You probably need to talk to Karen and choose the "Progress Main Story" option -- if you haven't done that after the quartz thing then this is the trigger you're missing.
Collect 5 Quartz > Karen cutscene > Progress Main Story > 2nd Synth NPC appears > Synthesize quartz with that NPC > Progress Main Story with Karen again to continue
EDIT2: And now I see I was ninja'd by AdventAnyx above. Oh well, two explanations for the price of one!
Apparently the game also has more than 2 maps now

Holy fuck
Wait, do you mean it has more than two world maps? Or what? Also, is there a second town/city at some point? I restarted from my first save and have sunk about 10 hours or so into a virgin run on the Endless Days mode (on serious difficulty, not maniac). So far I've just unlocked the bandit camp and am working through that quest.
Some unrelated questions for anyone who might know:
- How many costumes are there total? I think I've only seen 4 or 5 so far between my two saves, so I'm sure I'm missing some.
- Can you get Alcy to wear more revealing clothing with high exhibitionism alone? Or is it absolutely necessary to raise the Eros limit? I keep trying various things to see what we can get her to do while still being at level 0 Eros limit with 0 lust seeds (I have an ENF and shame/embarrassment kink, don't judge! lol) - so far I found a way to easily farm Exhibitionist points, I got it up to a little over 400 and haven't seen any changes...
- Do you get any benefits for playing or beating the game on timed days mode? Am I missing stuff by playing on countless days?
- What do lewd rumors do? You earn them by working in the underworld tavern, for example. I'm up to 94 and haven't seen any difference in scenes, but I'm guessing this is also tied to Eros limit..?
Man, this game is big. So much to do and unlock...