Oh good! I'm so glad that it's the conditioner you have. 14 drops per gal is what the directions on their website says so I'd have to use 42 drops for my 3 gal tank. That's crazy! I only use 2 drops per gallon of the Seachem Prime, I've had the same bottle of it for about a year now and that's with 4 tanks.
Given where your filter is and where he's hanging out, it might be the filter. First thing I'd do since it's a TopFin is checked to see if the flow is adjustable, I know the TopFins for larger tanks are, but I'm not sure about the smaller ones. If it is it'll have a little piece on top of the intake tubes that you can twist. If it's not then making a baffle is very easy. Since I'm a bit to tired to explain I'll let this guy on YouTube do it for me LOL, he demonstrates how to make a baffle out of a plastic water bottle.
The cloudy water could be from a number of things, but it should clear up relatively quickly. New gravel and new filter medium not being rinsed really well, and as the tank ages a bacterial bloom (harmless), can all cause it.
Since your tank is not cycled, and is only 3 gallons, I'd do 50% water changes every 3 days. Make sure to vacuum the gravel when you do the changes. You can use an airline hose as a vacuum, just shove it down into the gravel and keep moving it to a new spot. Once your tank is cycled you can switch to doing 25 to 50% (I usually do 50% on my 3 gal) once a week. Here's a link on how to do a fish in cycle https://www.bettafish.com/30-betta-f...-tutorial.html
I'd get him a couple more plants, it'll help him feel a bit more secure and the added bonus is that they actually hide less when they feel safe.
Here's a picture of the 3 gallon I have Lagniappe in, all the plants are artificial since I was not planning on getting him and don't have any spare live plants right now. He's already started coming out of hiding when he sees that I'm in the room.