Simons' journey through European football began at Barcelona, where he was hailed as one of the club’s brightest prospects. However, in 2022, he opted to leave the Catalan giants and joined Paris Saint-Germain (PSG) to seek more playing opportunities at the senior level. While PSG initially offered him a chance to make his mark, he was soon loaned out to PSV Eindhoven for the 2022-23 season.
Despite his successful loan spell at PSV Eindhoven, Simons found it difficult to establish himself at PSG upon his return in the summer of 2023. PSG, recognising his need for regular game time to continue his development, decided to loan him out once again, and Leipzig emerged as the option.