We report muon spin rotation ($mu$SR) and magnetization measurements under pressure on Fe$_{1+delta}$Se$_mathrm{1text{-}x}$S$_mathrm{x}$ with x $approx 0.11$.Above $papprox0.6$ GPa we find microscopic coexistence of superconductivity with an extended dome of long range magnetic order that spans a pressure range between previously reported separated magnetic phases. The magnetism initially competes on an atomic scale with the coexisting superconductivity leading to a local maximum and minimum of the superconducting $T_mathrm{c}(p)$. The maximum of $T_mathrm{c}$ corresponds to the onset of magnetism while the minimum coincides with the pressure of strongest competition. A shift of the maximum of $T_mathrm{c}(p)$ for a series of single crystals with x up to 0.14 roughly extrapolates to a putative magnetic and superconducting state at ambient pressure for x $geq0.2$.
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