Yes, progressing in Rollercoin is always slow. You need to know how to take advantage of events and also save RLT. Many people earn RLT and spend it immediately.
I, for example, try to maintain a decent pool to complete certain events like Puzzles. It doesn’t always happen, but sometimes when there’s a Puzzle Event and you complete the RLT Boxes missions in the first few minutes, you can get the big miner. This time, that’s exactly what happened. I ended up getting the 200 Ph/s miner with a 30% bonus!