As I see, even the worst, cheapest lvl 1 SA costs nearly 50kk with the soul crystal and gemstones. It just doesn't worth it, unless you can make a party and farm raids for the crystals. Or spoild the gemstones, which sure isn't viable way.
I'd enchant my weapon to +4 but I'm a bit scared of breaking it tbh. And knowing my luck, I will break it going to 4. Thanks for your response btw, I sorta figured out this thing eventually..