Lubala was born in the Democratic Republic of the Congo and raised in Leicester, England, where he attended St Paul's Catholic School. As a youngster, he played football for Carib SSFC, Leicester Nirvana and Friar Lane & Epworth. He was noticed by representatives of Birmingham City's academy while playing in a trial game in 2014, and took up a scholarship with the club that summer. Interviewed later that year, he assessed his strength as his attacking play, and felt he needed to improve his left foot.
Birmingham City
He signed his first professional contract, of one year, in April 2016. A year later, after playing regularly for the under-23 team, he signed another one-year deal, with the option of a second year. He played in the first team's pre-season friendly against Kidderminster Harriers, and in February 2018, the club confirmed that it would be taking up their option on Lubala's contract. With Che Adams suspended and Isaac Vassell and Sam Gallagher injured, he was included on the bench for the Championship fixture at home to Burton Albion on 7 April. He remained unused, but made his debut three days later, away to Bristol City, replacing Jérémie Boga after 69 minutes with his team 2–1 behind; the match ended 3–1. Lubala was a regular member of the first-team squad in 2018–19, and the first few months of the season was frequently included in the matchday squad. He made one start in the EFL Cup defeat to Reading and three fleeting substitute appearances in the Championship. At the end of the season he was offered a new contract, of one year with the option of a second, but no agreement could be reached between club and player.
Crawley Town
On 21 June 2019, Lubala signed a two-year contract with Crawley Town, managed by former Birmingham City coach Gabriele Cioffi. The deal included an option for a third year and an undisclosed sell-on clause. He scored in each of Crawley's first four League Two matches. Away to Carlisle United, he "shook off a challenge and cut in from the left before firing a low shot through the legs" to tie the scores before the hosts won 2–1, and at home to Salford City, he converted a penalty to open the scoring and had several other chances as his side won 2–0.
