Yes, no problem with not knowing which way to go for now. I think we all get there sometime! So maybe just some thoughts on the basic what and why may help to ease the worry and get things moving along.
My views and that may not fit all the other thinking the group has.
My view is that fishless came into being when we got around to wanting to get a whole tank of fish shipped in and one way to say on the really expensive shipping is to make one box do the whole job! Cichlids coming from Africa made this important.
So if we are going from no fish to 25, we got to have a BUNCH of those little bacteria to convert from ammonia to nitrite and the other group then grows to convert deadly nitrite to far less dangerous nitrate. To control it and make really sure, we used pure ammonia without surfactants ( form of detergent!) as "food" for the first group. It often takes a couple weeks for this group to really grow in, so we keep testing the ammonia amount to keep it at the ideal level as we wait and hope to eventually test and see nitrite. Then eventually (maybe a month!) we get around to seeing we can add ammonia of a certain amount and see it converts to nitrate the next day, telling us we have the super sized colony of both types and ready to add fish. We do a massive water change to knock the nitrate levels down so we don't harm our terribly expensive fish coming all the way from AFrica!
No big deal to take a month of testing and sweating if they want to protect a couple hundred dollars of fish they may never be able to replace!
But not really what many of us need/want if we are going down to the local shop to buy a handful of fish that may cost $20 and everybody has them, so we have evolved/ changed our thinking and there are dozens of different levels of doing the same idea of getting bacteria to deal with the waste.
Lowest level, is to slowly add a couple small fish ,letting the bacteria grow to meet the new food source, before adding more and getting more ammonia. Not the best as it tends to do some level of damage to the gills of the fish and they do tend to not live as well.
Another way, is to swap or someway get some used filter media as it has the "start" of both types of bacteria and if we keep them fed, they grow pretty quickly, so we can add more fish sooner if we watch the ammonia level carefully and do water changes to keep it down. Works pretty good if we are careful to not damage our fish.
With plants, we get into more where you are now, I think. You will be getting some bacteria growing as it is all over in the air, etc. Got a tank, it shows up to eat! Adding bottle bacteria can speed this but it has doubters as the bacteria dies if the bottle gets shipped and too hot! Some like it, some can't see any benefit.
What complicates your situation is that you may be seeing nitrite and nitrate but it is not likely to be from the bacteria that quickly but from any ferts you are adding?? But plants also use ammonia and ammonium as plant food!
So how to proceed is a personal choice thing and depends on your situation.
I live where the fish mentioned are easy and relatively cheap to acquire, so I would get a few which depends on what size tank and how much work/worry to do water changes. For instance in a 20-30 gallon tank, I might add five small fish like guppy or tetra and not worry much about it, while still doing the careful watching needed for any new tank. I'm from a farm background where we grew up knowing that things have to die at times and it doesn't bother my thinking if I do slip up and damage or kill a few. It happens! After a week or two and all looks okay and the ammonia level is not too high or working me too much changing water, I then add a few more until I get all that I want. I rock the boat but gently until I see how it goes?
On using Prime, I am very much in favor of it as treating water to neutralize the chlorine or chloramine in tap water and it works almost instantly, os I often just drip some in the bucket of new water and pour it in. I'm less inclined to use it as a buffer for ammonia as it tends to mask what problem I may have. If I'm creating situations where I get ammonia readings, I tend to want it to show up so I can fix that problem, not be hidden by using Prime. If I am making a mess, I change water and change what I'm doing and don't want the faults to be hidden.
It is a balancing act and we do each have to get into the flow of things just like riding a bike. Most of us do the best we can but still fall off and skin a knee now and then!