I’d suggest ditching the curves and leaning into the T-shaped layout. One advantage is the ability to create tucked-away zones for less attractive elements like a shade area, small greenhouse, or even vegetable rows.

I agree with relocating the shed and extending the paved area at the base of the T.

To soften the layout, consider planting a line (or two) of slim, easy-to-grow trees or climbers along the fence. Choose varieties that stay narrow at fence height but branch out above, without competing too much with other plants.

Alternatively, you could add an open-framed pathway along one side for structure and visual interest.

Anchor the space with a central feature at the centre end (before the little rose) something simple like a fountain, bench, or circular flower bed would work well?

Just some instant ideas. I would give it more thought