After watching season 4, I realized that only the manga has ended, not the anime…
And although the anime is excellent, I had read about 50% of the manga in the past, so I knew it’s also great and follows exactly the same plot, and thus decided to read the final chapters, instead of waiting for the final half of season 4.
(I generally try to avoid starting a TV series that is still running.)
Found the chapters online at https://ww7.readsnk.com/manga/shingeki-no-kyojin/ - started at 115.
Great manga, great show.
Most significant thing I didn’t like were the continuous 180 opinion changes of most of the characters. Other than that, I enjoyed it very much, start to end.