The Nautilus is the only companion that is literally designed for all of the primary game modes because it can do railjack repairs and can heal the player, so next to the [Helios] and Death cube prime, its in the top three sentinels in my book. Its also because it can group enemies together like a sudo-sentient larva, so pretty POG in my eyes XD.
Keep in mind that this is how I build MY weapon's an warframe's, they work really well for me, so if you are one of those people that is going to to go into the comments and give me shit is to how I play the game, I will kindly ask you to put a tooth pick under your toenail and kick a wall. JOKINGLY OF COURSE.
If you do decide to follow my builds don't get butthurt if your numbers aren't the same, all the riven's are the ones that "I have rolled" so don't psyche yourself out if you don't get a riven that is a good as the ones in my builds.
Be sure to take a look at my other builds. I also recommend looking at the vault status of all prime variants in the second link below. If you want information on the quests and the requirements, I recommend looking on the actual Warframe website under the game dropbox to look at the warframe profile videos as well as looking at the quest guide and the faction types. Click the third link below if you are interested.
Wiki:
https://warframe.fandom.com/wiki/Prime
Warframe website:
https://www.warframe.com
My Guide for new Players!:
https://docs.google.com/presentation/d/1NDLcIbpVdBX559tW5RVLdmoZ1lNnf_3CsjMLL1KKtco/edit?usp=sharing