even given that we're talking about a top-tier village, you need 3 things for a soldier: stats, skills, and equipment
so let's look at what it would take to create a basic soldier:
for stats, you want str, agi, and con. you can forgo int (since it's just going to be studying pearls, high int isn't needed, really), per, dex, and psy as your sole purpose is combat. you'd want to get about 100 in each stat, which is 270 fep bars full. that's quite a bit of food, and even if it was already produced and stockpiled it would take some time to eat.
for skills, you obviously just want a bunch of combat skill. let's say we're going to get 100 ua and 100 melee, plus all the relevant combat skills and black skills. that's a little more than 1 million LP, for an entry level combat character. so let's go with your example of giving it pearls as curios. obviously the character needs to get full peace/change first, which takes a couple days. then, at 420% LA from pearl gear and tea, that would be 21k per hour and would take about 48 hours, and of course, 48 pearls would be consumed. bare minimum of 4 days, around the clock.
and finally, you have the equipment cost, which can vary widely but lets assume steel plate, helmet, sword, gauntlets, pearl necklace (on loan, at the very least), necro robe or merch robe optional, i suppose. and of course your leather pants, vapnetreyu, and either leather boots or ranger boots.
obviously we're making a lot of assumptions here and completely ignoring the infrastructure setup that would take weeks or months, but it should be fairly obvious that you can't just "randomly become a supersoldier overnight", and even given the accelerated timeframe of 4 days, we're talking about a considerable amount of work and resources here.