Steep times for NB kits when making 5 gallon batches

Curiious as I am new to homebrewing, I’ve only brewed three batches so far. Buying all my kits so far from NB.

All recipes are calling to make 2.5 gallons worts. However, I am brewing w/ a turkey fryer and 7.5 gallon kettle and have been making 5 gallon worts w/ little additional water added at the end (just enough to get to 5 gallons after boil).

Unsure if I should be adjusting the recipes at all. I haven’t so far and have been happy with the results, but am unsure if I should be steeping longer than in the recipe - recipe calls for 20 minutes or until 170, curious if I should be steeping longer due to additional water?

Also, for aeration I have been vigorously dumping the 5 gallons between the brew kettle and the fermenting bucket back and forth five times. Do you guys think that is enough?

No, the steeping times are the same whether you do partial or full boil. At most, while doing a full boil, you get better hop utilization.
I generally (when I do extract) is steep in 1 gal of water separately on the kitchen stove. Then add that to the water I have heating for the rest of the brew. Depending on a few factors (like alkalinity of your water) that doing it in more than that can leach tannin.

Just member to use what the AG recipe uses for the hop amounts not the extract when doing full boils.

Steep the grain in 1g of water in your kettle and then add your other 5-5.5g or so, or do it in a seperate kettle on the stove and add to the other kettle when done to save a little time.