I had what felt like YEARS of experiments with different adhesives, with mixed results. I use 2-part syringe plastic epoxy now, but I also don't build as much as I used to.
In regards to strength between parts/ etc, a habit I picked up a long long time ago was to run 5.4 mm channels between pieces to strengthen the joint and help with alignment.
So on the blade of a sword, I'd run at least 2 channels out towards the edges, and then use steel rod (cheap and available at hardware stores) to shish-kebob the parts on as I glued them together; the rod adds strength, and the multiple rods also make the parts align more properly. Just run adhesive down into those channels before assembly, and even smooth rod grips and works awesome. I have used threaded rod as well, but really I didn't notice enough of a difference to spend the extra money. Also,
why 5.4mm? Because if you sell or distribute your files in europe/etc,
5mm rod will work great.... If you are stuck here in the USA,
3/16" rod is compatible in those same holes.
I also use those same channels between large parts just for alignment, so the rods only go into each piece maybe 2-3 inches. Cut a figure body in half, one channel in each of the four corners or the mating surface, and then it doesn't shift when you glue. I used to add slots and tabs, but I like those joining surfaces being flat so I can orient them like that with no supports when printing.
Anyways, I dunno maybe everybody else does this already, but it's my go-to for rodding parts. It won't save from damage when dropping a 5 foot sniper on the ground, but the rifle also won't explode into a pile of Legos either