I agree. My ten gallon tank was the first I ever had. The plants died very quickly. The floating plants lasted longer, and the plecostomus couldn't bother them. I used a special lamp. That just caused algae. I would settle for a natural rocky base and a natural looking substrate. I stayed in the hobby for about 10 years and raised literally thousands of fish, including Pearl Gouramis and Black Angels. but I found plants to be a pain in the neck. As for the heater, I completely agree with you. Talk to the aquarium where you bought it. It could crack from overheating and having the water hit the part that is not immersed.
I was surprised to see that the owner of the aquarium where I traded fish for supplies did not use a dechlorinator, so I never used one again. It's possible that I kept my tanks a bit too clean for the plants. I had an automatic water changer-a blessing for anyone with many aquariums. I also moved Angels for breeding to a newly setup tank with no preparation other than clean, warm, water, raised the temp., and they bred. No problems. Then I took the parents out as soon as I duplicated that clean water situation in the 55 gallon tank and moved the parents. Only a sponge filter is safe for most egg layers' fry. They're tiny!
But I paid my dues. As I went along I read about ten years worth of TFH and I had a large reference book, which I also studied and referred to. When I first started, I did everything I was told. I bought inexpensive fish and a catfish to get the filter "going." I left it for days, everything according to instructions, and EVERY fish died. I consider that "my dues." I replaced the fish.
Oh, Corydorus (catfish) lived through that. He was my longest living fish, and Don Juan, a male Angel was the next to oldest. I was upset when each of them died. I never thought anyone could get attached to a fish!
That was the last problem I had. However, if you get any tetras, don't just float the bag; acclimate them by gradually changing the water in the bag with the aquarium water. I have seen them hit the water and nose dive to the bottom of the tank. That's because the store might have a different PH from your water supply. It's wise to do this with all fish, of course. Good luck. Don't spend a lot on plants, please. Wait until you are more experienced. You'll be more successful.