If you’re using Private Torrent Trackers and have built up a good ratio I’m sure you would get pissed off if you suddenly got banned because of messed up settings in your Torrent Client.
A couple of years ago it was recommended that you turned off DHT and PeX when using Private Torrent Trackers because it brought in people that wasn’t members of the Private Tracker and let them download stuff too, which would affect the Private Tracker in a negative way.
But things have changed since then, at least when it comes to QBitTorrent.
If you’re using another Torrent Client you have to look up if they respect the Torrent-files private flag in the metadata. Most Torrent clients that are up to date will handle this for you.
So in QBitTorrent you can enable both DHT and PeX which could help you find more seeders and peers which could help to increase the Torrent download speed. And when a torrent is marked as Private in its metadata, qBitTorrent will automatically disable both DHT and PeX for that specific torrent, even if you have them enabled globally.
This is by design and follows the BitTorrent protocol specification for private torrents.
So it’s generally safe and recommended to enable both. You’ll get better peer discovery on public torrents, while private torrents (typically from private trackers) are left untouched and rely solely on their own trackers as intended.
There’s also some other ways you can find more Torrent seeders and peers if you think the download speed is too slow.