I just picked up a 28 gallon hexagon tank and need tool recommendations and design suggestions please!

A shoal of pea puffers are going in it so I need it as heavily planted as possible while still looking intentional in design. I've got this big piece of driftwood i plan on glueing java moss to and using as the centerpiece but thats as far as my planning has gotten.

Overall, its probably going to be low tech; ive got good lighting but no co2. currently using seachem root tabs and dosing flourish but open to suggestions for a substrate layer under the sand or co2 kits if you think that would be best. here's what I have so far that I'd like to include:

-white aragonite sand -anubias barteri, hornwort (this ones negotiable, i kind of hate the look but the puffers love it), moneywort, amazon sword, dwarf sag, red melon sword, anubias coin, hygro araguaya, java fern, java moss, a TON of val, cabomba -12" driftwood that i can cut down smaller if need be

need suggestions/recs for:

-a good light that will reach down to the bottom (~23") -substrate suggestion for under the sand -a long but small in diameter gravel vac or DIY tutorial -general design suggestions/inspiration (ive only ever done square tanks with an obvious front and back, this will be viewable from 5 sides)

i really only have experience with walstad method nano tanks so ill take whatever advice i can get. thanks in advance!!