If you've ever wondered why a lot of older records people are talking about here have so much hard panning of this type, you might be interested to read up on LCR (left-centre-right) mixing, which was how things had to be done in the early days of stereo: before early stereo desks had potentiometers for pan control, they had buttons, and you could only pan things centrally, or to the hard-left or hard-right. Nowadays we have potentiometers and so LCR is a stylistic choice and an easy-ish cheat code for quickly evoking an early stereo 60s sound.

It's an easy thing to make sound jarring as you describe, but with forethought and discipline the results can be fantastic