I gave up in season 6 after Quinn died.
i think I tried a couple of season 7 but it didn’t interest me.
I might watch the finale but it may not make much sense to me now.
It might be season 6 that I thought wasn't as good. The one before the finale got better after about ep.5 I think. I vaguely remember it was quite slow to get going with not much happening each week.
You might want to watch the end couple of episodes of Season 7 for the full back story
to Yevgeny and Carrie's relationship. Although you might be able to get enough info from the recap at the start of Season 8, ep.1 and the references they make to it throughout the series. A lot of new things happen too that don't require much prior knowledge of past seasons.