Thanks for this which is very helpful. My failure with dry hopping and hop tea puzzles me too. All I know is that for the most part beers I have dry hopped or added hop tea to have tasted too sharp to begin with and have oxidised sooner. As I am having to cut down and as I prefer to do 23l batches the product needs to still to taste good after several months.This year I have dropped my abvs and I am really enjoying drinking beers that are mostly under 4%. I having been doing AG batches between 8 and 16 litres. I bottled a 14 litre batch today, a 3.8% pale with Chinook and Centennial hops. I also added cherry puree which I made myself to 8 litres of saison which will be about 4.5% iirc.
I make these on my cooker and it's not challenging. I could easily make these up to 5 gallons by adding plain extract or a kit can. Kit cans have the advantage of giving you the bitterness you need. Use a simple low colour kit, like a lager, or Canadian Blonde etc. Or Muntons hopped extract. Or use unhopped and do a bittering addition in your grain boil. To hit 4% ish:
OG 1.042. FG 1.010.
1.8kg Pale malt
I don't understand your problem with adding hops to kits. Always worked well for me, dry hops or hop tea.