Phosphorus is an essential nutrient, considered a critical raw material by the EU, with its main source being limited phosphate rock reserves that are not evenly distributed worldwide. Therefore, in this study, P recovery from an alternative source, the solid fraction of digestate (SFD) and N-stripped digestate (SFND), was investigated, using alternative and recovered acids as P leaching agents. These acids included waste sulfuric acid (WA), citric acid (CA), and scrubbing waters from the N-stripping-scrubbing of digestate in the forms of ammonium sulfate (AS) and ammonium citrate (AC). The resulting P-rich leachates were used to produce struvite-rich biobased fertilizers, and the remaining carbon (C)-rich and P-poor solids were assessed for their potential as soil improvers. The P-rich leachates were then subjected to precipitation to form struvite-rich products. These products were evaluated as potential P-fertilizers through pot trials, comparing them to a commercial mineral fertilizer. Finally, following P leaching, the residual (C)-rich fractions were evaluated for their soil improver potential in a C-incubation experiment. AS and WA performed similarly to sulfuric acid as P-leaching agents on the SFD (30% of P recovery), while CA and AC outperformed sulfuric acid when applied on the SFND (up to 62% and 56%, respectively). Almost all the P was recovered in the form of struvite in all conditions, except for the precipitation performed in the leachate resulting from CA and AC as leaching agents, where struvite formation was hindered. In pot trials, the struvite-rich products resulted in a P fertilizer replacement value (PFRV) of 85-105% in the final harvest, proving to be good alternatives as P-rich fertilizers. The C-rich products had low C-mineralisation values (~15%) and high effective organic carbon (~78%), indicating their high potential to act as soil improvers in the long term.