They handled that well, thats a direct swap of another character in the book that died in the same way (Fred Johnson). In the book, Fred was with them after the attack on Tycho station hunting Marco and he stroked out during a hard burn.So. The Expanse killed off Kamal (because the actor was being a creep IRL), but they've pretty solidly set up Bull to be his replacement for season 6.
Last I heard, they were stopping after season 6 (which would be the pursuit of Inaros/Babylon's Ashes), and yet at the very end of season 5, they cover the Barkeith heading through the ring to Laconia, and the end credits of the ep show the Laconia shipyard. I don't see how they could possibly do the Laconia arc + the end of the Free Navy in 10 episodes.
Here's hoping for some more seasons, I guess, rather than skullfucking the last season like GoT.
Its an appropriate place to "pause" the series once they get Marco. The other books are almost a phase II since theres a time jump, and the whole duarte/"darkness between the spaces" timeline is a separable story.
They wont do the laconia arc, thats part of the time jump. The laconia gate stays closed up for like 10-15 years.