There are several units of measurement for hardness; fishkeeping uses just 2. Degrees Clark is not one of those two so we need to convert it.
Your hardness is 2.1 dH and 38 ppm. Fish profiles will use one or other of those units so you need to know your hardness in both.
It is indeed soft water so you need to look at soft water fish. The fish you suggest in an earlier post are all soft water
The best place for researching fish is
https://www.seriouslyfish.com/knowledge-base/ Their profiles will tell you if your water is suitable for them, if your tank is suitable for them (though with the size of yours only a few tank busters won't be suitable), whether the different fish all need the same temperature, whether they will go together or try to kill/eat each other etc.
Back to basics - cycling. There are two ways to cycle a tank without risking the fish - fishless and silent or plant cycling. Fishless is explained here
https://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/
Silent (plant) cycling uses plants. I don't know if you are planning to use live plants but if you are, this is an option. This method relies on the fact that plants take up ammonia as fertiliser and they don't turn it into nitrite or nitrate.
Silent cycling involves planting the tank quite heavily with fast growing plants and floating plants. One or two slow growing plants isn't enough. The plants are then left to establish themselves and once signs of new growth appears, the fist batch of fish can be added to the tank. It is sensible to test for ammonia and nitrite every day to make sure they are remaining at zero. Once you are certain of this, the next batch of fish can be added.
The third cycling method is fish-in cycling which is not the best method as it risks harm to the fish.
Some members disagree, but most of us do at least 50% water changes every week.
