Alright, this looks like a fun thread. Pic related is test data collected from test reports and Buffman's test videos of both XSAPI (revision A / B) plates and the Adept Colossus VPAM PM-12 plate, which is moderately stronger.
To defeat an XSAPI, you need to take .30-06 M2AP, the Level IV threat, and reload it into a cartridge fast enough to go well over 3,200ft/s. To defeat the Colossus without using exotic tungsten-core ammo above M993 / Swiss P AP, like 7.92x57mm SmKH or 7.62x54R 7N37, you'll need to drive M2AP well above 3,300ft/s. This can be done using a .300 Weatherby or equivalent, but this isn't something you can CQB with. If you can get M2AP to 3,500ft/s you have a decent window.
The only plate above the Colossus in this area that is actively in CONUS is the Protech 2230, which is rated to defeat .30-06 M2AP at 3,500ft/s - a stiff requirement that you can probably guess as to why it exists. It's a heavy fucker at 7.5lb and was discontinued many years ago. They were surplused out from LE a few years ago on the cheap. Possible there's something better out there (Protech 2240?).
The better answer is to train for pelvis / femoral shots to go around the plate. Better yet, explosives. The first option will be difficult if they have Level IV or above shields. Known extremity armor has yet to exceed NIJ Level IV. Helmets have yet to exceed M855 / 7.62x51mm M80 protection aside from vaporware like the Diamond Age Bastion (M855A1) and extremely heavy Level IV overhelmet appliques from Tencate.
>How are you planning on defending your property if a state actor wants to take it?
No be there, said Mr. Miyagi.
>other two glowing questions
Not answering that on a public forum neither should anyone else.