Additionally, even leaving aside the stuff that implicates him, the idea that someone else could've pulled it off in such a narrow time frame, apparently using the Murdaughs' guns (I'm still not sure whether that's been demonstrated conclusively or it's just a preponderance of the evidence type deal), seems really unlikely.
How long was Alex actually gone from the property when he went to his mom's house? I think I heard he was at his mother's for about 20 min. Don't know how long a drive it was there and back. It just seems a stretch to me that someone showed up at the property, procured the weapons and caught Paul and Maggie at the kennels, killed them, stole just Maggie's phone, not Paul's, and then tossed it out the window as they traveled the same route as Alex to his mom's house.
If it really was the Murdaughs' guns, then of all the stupid shit he did, that would be near the top. Not getting rid of both phones was another one. Having not a drop of blood on him when the first responders arrived was another miscalculation, especially if you're claiming you touched the bodies. For a smart guy, he clearly panicked.