There is no need for “ boutique blends “ for a simple plant …. Especially from a hydro shop.
All of the initial “ feeding “ can be done by available bagged mixes - most needing minor tweak but overall ready out of bag. Buffers and all.
Then you can top dress the same mix as a supplemental feed or “ recharge “ of medium as plant consumes at its own pace. Or as stated a simple dry fertilizer ( scratched in to top soil ) and watered in.
You would find a better ratio of elements already available in those bagged mixes including myco .