It’s been a couple years since I set it up so I couldn’t tell you what’s the best deal these days.
I use Newsdemon’s 2tb/mo plan (Black Friday deal, it’s almost free it was so cheap) and a Blocknews block for completion. I don’t have any issues with downloads being incomplete but YMMV.
Nzbgeek indexer (lifetime sub), Sabnzbd downloader, and the full *arr suite for automation, and an Emby server running on my NAS.
I just looked at the current offerings from Newsdemon and the deals are not nearly as sweet as the plan I’m on. I suspect that your best bet for a long-term subscription would be to wait until Black Friday, but there are plenty of providers with cheap blocks or monthly plans to play around with.