Counterintuitively, when you're using your Uno as a USB-TTL serial adapter to allow your ATtiny85 to communicate directly with Serial Monitor you need to connect the software serial TX pin on the ATtiny85 to the pin marked TX on your Uno (pin 1). The reason is that marking on the Uno silkscreen is referring to the pins on the primary ATmega328P microcontroller on your Uno but you're not communicating with that microcontroller, you're communicating with the USB-TTL serial chip on the Uno, which is connected to the ATmega328P RX-TX, TX-RX. So the pin marked TX on the Uno is actually the RX pin for the USB-serial chip on that board.
You also need to check the pinout for the ATtiny85 hardware definition you're using. On both the most popular hardware packages the pin you have connected to the Uno's RX pin in your diagram is Arduino pin 3, not 2:
- GitHub - SpenceKonde/ATTinyCore: Arduino core for ATtiny 1634, 828, x313, x4, x41, x5, x61, x7 and x8
- attiny/pins_arduino.h at master · damellis/attiny · GitHub
Note that the Arduino pin numbers don't necessarily match the physical pin numbers on the chip. Arduino pin numbers are just an arbitrary designation to make it easy to refer to a specific pin.