I just finished book 4, some chapters of which I started skimming (mostly the Venli/Eshonai throwback ones). I want to finish the series but it's such a slow burn it's getting tough, especially when I have other books on my TBR. I'll get around to book 5 sometime next year.
I did really enjoy the first book, kinda want to go read it again.
Ah. I know what you mean about Venli/Eshonai throwbacks. Those gave me a few "ugh here we go again" moments on my read through, but they do build up to give more context about the Parshendi and how/why the current conflicts starts and who they are as a people (trying to avoid spoilers as much as I can). I still think it's a bit of a slog, but I appreciate it a bit more now...
I hated book 5. I thought 4 was the worst of series until I read 5.
The ending was just really shitty and stupid to me.