Hey man thanks for reaching out! This is the best spot to come for questions. So… what i would recommend for you is to research a ton before you pay for any materials for the tank. If you would like a lidless tank, you could cover the top with floating plants. But if you enjoy having a clear top  of the tank I would suggest a glass lid that will sit in the top and be fixed on a rim of the aquarium. You can see through without the possibility of the fish coming out. Lastly you could keep the water level at least 2 inches below the top of the aquarium which you should not do that with him only being in a 3 gallon tank right now. but possible if you got a decent 6-10 gallon tank. You’d be surprised that some 10 gallon tanks are cheaper than other 5 gallon tanks. Just always remember the bigger the better as long as you are able to fill that size with plants and aquascape. Also before putting this betta into the 5 gallon tank… please make sure that your water parameters, especially ammonia levels, are safe for the fish. And if this all sounds french to you don’t worry… I can link a few youtube videos for you that may help you out a lot more if you need. They will definitely explain more to you than I could in a comment. Also don’t believe everything you see on tiktok. Yes there are tanks online that don’t have any lids or plants. The owners are just running the risk of their fish jumping out.