The secret to an easy aquarium is live plants imo.
I'd start with 15 gallons personally, but you can go higher since more water means it's more stable. More water does mean harder water changes.
I usually try and aim for a more natural aquarium, I usually fill mesh bags with dirt and then pour sand over it (I like black sand). I aim for 2 inchs in the front, three in the back of more (a gentle slope is really important lookwise).
If you pick easy plants, you won't need much lighting, I have one bulb from above angled and a cheap Amazon led light directly above it. Look up the plants online and aim for something that doesn't need CO2 or intense lighting. In my current one I have: Christmas moss, dwarf sword grass, polysperma rosanervig and water sprite.
I basically plant and then add water, I wait a week or two, then add snails (super important, just get bladder snails, your local fish place will probably be okay with giving them to you, they are technically pest snails but they do good cleaning up). A week or two later if my parameters are good, I add a few shrimp. Then after a month or two aonce the shrimp have bred and their young are a good size, I add fish.
For fish it really depends on what you want, you will have to look online. I only get nano fish really since the bigger ones will eat adult shrimp (eating shrimp babies is fine tho). Shrimp are super cool and keep the tank clean for you so they are a must in my tanks. Fish are added last. Some fish like pygmy corys can be clean up crew as well.
Never ever get live breeding pairs of fish or live breeding females (guppies, platies, etc). They over breed and out compete everything in the tank, females give birth months after their last breeding. Males are fine though, and guppies cannot be killed tbh.
I also like to add a purple mystery snail, there's a lot of really cool snails, as well as an amano shrimp sometimes. African dwarf frogs can be cool too, but are rough on plants. There's more than just fish. Depends on the size of the tank and all. Some fish jump out more than others.
I have a simple sponge filter but tank kits usually come with a hang on back filter. I like the little magnet sponge to make cleaning the glass easier. My lights are on timers and I have an auto feeder that lasts a month. I change about a bucket of water every month, as well as prune the plants. If you want, get an autofeeder with little compartments, not the one that has a screwing motion. Also an air stone and compressor are also a must.