I'll give you the basics:
You don't need to feed some plants ANYTHING unless they are deficient. If you get a deficiency chart online that will help or just look it up if the plants look unhealthy. You will probably need to feed most plants either NITROGEN and/or MAGNESIUM. Nitrogen is easy to get with fertilizers get something natural dont just get that water in a bottle crap. And the soil you have is probably fine. some plants might need a bit extra. For magnesium you can literally just buy food grade epsom salt.

I can specifically tell you not to use calcium because people talk about cal/mag a lot like they are the same thing but they ARENT and the one time I added grinded up egg shells I only used a few shells for my big plants and it shocked my plants a LOT so be careful just adding calcium. If you google what I said it wont agree but I can tell you my plants got shocked so it's good to try to figure out deficiencies in real time first.

AND EVERY PLANT IS DIFFERENT. SO RESEARCHING IS ALWAYS GOOD

The biggest mistake literally every grower makes with their plants and Im going to help you a lot here so if you are confused by what im saying at least trust me on this part. LITERALLY EVERY GROWER OVERWATERS THEIR PLANTS THEN THINKS ITS A DEFICIENCY. overwatering causes nutrient lockout. Of course, you can underwater and kill the plant, but overwatering is super easy too just use your finger to test the soil and let it ALMOST dry out before watering again.