If you have gravel, it can be hard to plant unless you use those long aquarium tongs. So, if you have the money get a pair. they do sell sets, but in all honesty, the tool you'll prob use the most is the straight tongs. I just stepped on one of mine though and was looking around for a pair where I wouldn't have to buy the set.
I found Sagittaria subulata to be easy for me vs Vallisneria I couldn't keep. But tons of people have the opposite. But, I do find the Sag to be easy and sort of like tall grasslike if you put in the back. But the ones I mentioned above are the ones that will absorb the most nutrients. Hornwort, as long as you have light you can let it float and do nothing. It'll absorb nutrients and help reduce Nitrates. You get get a couple bunches and they are cheapest. If it does shed leaves just siphon them up and use Seachem Excel. Guppy grass is probably the easiest. But depends on what they have I guess. When you get there, look up the name on your phone.If i find the plant site I'll add it...
Ok, this plantfinder might help. Or this post as good beginner plants, but it does say Sagittaria subulata is Dwarf Sagittaria which it isn't. If you don't find any you can look on r/AquaSwap too.