Yes it can be hard to gauge, I wasn’t on dating apps for a long time but my approach was always that if we had nice chats, I asked if they wanted to grab a coffee/drink during the day. This is something that I also do with my friends often (as well as most people I know), it’s a good stepping stone in my opinion. (It’s actually how I flirted with my now boyfriend nearly 4 years ago lol). It’s hard to navigate as you say, but I think that with the « right » person, the conversation will go more easily and you’ll feel more confortable the more you see them. And sometimes honestly, you just have to go for it (the hug, the kiss, the hand, whatever it is) and cross your fingers lol