Seat Alhambra Brake Fluid Low Pedal Feels Strange

Low brake fluid and spongy pedal? Classic signs. First thing, inspect all your brake lines for leaks. Given the Alhambra's age, check around the master cylinder as well; seals can degrade. Any warning light illuminated on the dash? If your brake pads are worn thin, the calipers need more fluid to compensate, lowering the level in the reservoir. But that much feedback from the pedal… I'd err on the side of caution. Don't just top up the fluid without investigating. Last time I ignored a similar issue, I ended up with a seized caliper. Not fun.

Brake lines seem okay on visual. Pads I'll need to check, but the pedal feel is definitely off. Could a failing master cylinder cause this even without visible leaks?

Yes, a failing master cylinder can absolutely cause that, even without external leaks. Fluid can bypass internally, leading to poor pressure and a spongy feel. Given the symptoms, and that you've checked the lines, I'd strongly advise getting the entire brake system inspected by a professional. It is very likely worn brakes though. Don't risk it with brakes.

Confirmed. Brakes were indeed worn. Full replacement, fluid replacement, and system check later, and pedal feel is back to normal. Cost me 480€ Thanks for the insights.