They can record it in two times this time : one part where the band without Bruce composing the songs in march, another part in late july/early august where Bruce putting his voice on the new songs already recorded by the rest of the band in march/april/may. The band, including Bruce, surely had plenty of ideas during lockdowns (as Bruce said in interviews) and as the band wanted to book a studio in 2020 or 2021 after having recorded 'Senjutsu', it means they had already demos of new songs done at the time. So, for me, it's possible for the band to record something in march/april/may and after that to put Bruce vocals on them in early august.
OR, there is another possibilty : Adrian is the only member of the band in Paris now and will rejoin Bruce to work on new Maiden songs for the next album. Janick and Steve are working on songs together, Dave maybe. And then, Kevin will rejoin them all in Sydney and will start to talk with them about the new album recording in Paris in early 2025 for a release date in september 2025.
OR, the album has been already recorded in Caveman studios in Australia and is about to be mixed and mastered by Kevin, that will present the result to the band in Sydney this september.