Generally speaking, it is unsinkable. In fact, as long as you keep breathing rhythm and don't spit out all the air in your lungs, you won't sink even without a floating board.
Binding floating objects to the body will not affect the activities of hands and feet, but if it is impossible at all, it is recommended to start learning by kicking, which is actually very simple.
Swimming rings are not recommended, because you will never learn to affect the activities of your hands. Life jackets can be considered, but in the swimming pool, it's a bit strange, isn't it?
So skirting boards and floats are the most suitable. Kickboards and floats are also used in regular training courses ~
Ps: I've been in the water 1 1 year ~ I can swim all four strokes ~ I used to be a professional athlete ~ hahaha ~ I wish you success.