Blacksmith texts are certainly elusive creatures. When I was farming all texts for Master of Illusion build, I had to fight Danzo (aka Flying Kato) probably 30 times at dojo before seeing armour text but as luck would have it, had gotten Swift Hawk text earlier in the process; takeaway is these drops are a must to re-roll and freely level-sync or optimise gear, weapons, charms + it feels VIP, of course.
Make sure you are fighting whomever has your text(s) with Kodama blessings for Materials as well as equipped gear/charms tempered for Item drop rate; Luck is not needed and targets rather items otherwise that have applicable rarity (grades) which texts haven't, AFAIK. You'll get everything you need sooner or later (it's not bad looking back but sucks when in the middle of it) and Benkei is a fun fight in a garden-like, treed nook, iirc -- get some!
On levels and armours across the board, I assume so, especially if touching the 300 ceiling. My char is sitting around 230 right now and I feel free enough to reincarnate in ways x, y, z but I crucially still feel I need choose my avenues before sinking points into anything. I imagine at 300, one can get sloppier and even set-swap without reincarnating, depending, which would be awesome. The new armour rarity (and level hard cap?) dropping on 15 October is going to shake things up so we'll see what the new status quo feels like.