They're mostly pretty good, except maybe CAFU.
You can go in for one series, or go in for several. You invest as much as you want.
XO Manowar #1-18
XO Manowar #19-22 sequenced with Unity #1-4
XO Manowar #23-25
XO Manowar #26-29 sequenced with Armor Hunters #1-4
XO Manowar #30-50
XO Manowar (2017) #1-
You can pick up any #1 or vol 1 and not be lost. XO Manowar (2017) is a good starting point with no background required. Secret Weapons is coming up next month. They have a handful of really good entry points in the form of miniseries - The Valiant, Faith, Savage, Britannia, Ivar Timewalker, Generation Zero.
I don't know how to tell you this because you've been tormented for 6 months by it, but this person is straight up wrong lol. I read through Harbinger without reading Bloodshot and nothing of value was lost.