Option 06 · Fails side clearance
This was my recommendation before I checked the numbers. The 6" offset that saves the window also makes one upright unusable.
Dashed outline = minimum clearance envelope, 24" each side and 36" in front · shaded = working zones · stair wall at left
I treated the trainer's working space as a rectangle projecting straight forward from its face, and optimized the corner offset purely against the window. That ignores the machine's 180 degree swivel pulleys, which direct cables sideways and behind, and it ignores the plain access requirement: you need to reach the weight pins and pulley adjustments on both uprights. Six inches is not enough room to stand in, let alone train in.
Published guidance converges on a 24" minimum buffer around the entire perimeter of a functional trainer, with 36" preferred for full-extension movements like flyes and crossovers. At 6" the corner-side upright is effectively against the wall.
The room is 123" wide and the trainer is 55" wide. That leaves 68" to split, or 34" per side if perfectly centered, already under the 36" preferred figure before you account for anything else. Any offset large enough to matter for the window drops one side below the minimum. The back wall does not have the width to be generous.
The instinct, keep the window, was sound. It just has to be paid for somewhere other than side clearance. Option 03 does that by moving the trainer to a long wall entirely, where side clearance stops being scarce and the window question never comes up.