B5 was envisioned in it's entirety, beginning to end, to be five seasons. IOW, the end was planned before it even started filming, much as five books with a certain number of chapters in each book.
They succeeded in that and when they tried to wring another season or two out of it it fell flat on it's face. Leave it alone.
FWIW. it's on HBO max now.
Please read post #6 - on the original planned story Arc from JMS -
But - direct from Wikipedia -
https://en.wikipedia.org/wiki/Babylon_5
During production of the fourth season, the Prime Time Entertainment Network, which Warner Bros. opted to use for
Babylon 5, was shut down, leaving the planned fifth season in doubt. Unwilling to short-change fans of the show, Straczynski began preparing modifications to the fourth season that would allow him to conclude his overall arc should a fifth season not be greenlit, which ultimately became the direction the fourth season took. Straczynski identified three primary narrative threads which would require resolution: the Shadow war, Earth's slide into a dictatorship, and a series of sub-threads which branched off from those. Estimating they would still take around 27 episodes to resolve without having the season feel rushed, the solution came when the TNT network commissioned two
Babylon 5 television films. Several hours of material was thus able to be moved into the films, including a three-episode arc which would deal with the background to the Earth–Minbari War, and a sub-thread which would have set up the sequel series, Crusade. Further standalone episodes and plot-threads were dropped from season four, which could be inserted into Crusade, or the fifth season, were it to be given the greenlight.[29] The intended series finale, "Sleeping in Light", was filmed during season four as a precaution against cancellation. When word came that TNT had picked up Babylon 5, this was moved to the end of season five and replaced with a newly filmed season four finale, "The Deconstruction of Falling Stars".
So - the actual planned Season 5 that aired on TNT was a bit weak with the main story arc already concluded. And the actress who played Ivanova had already accepted other work before the 5 season funds turned up, so sadly, she was not in the final season.