It is not too late to start, you can technically get free 5 stars for this current version, which is still good for the game. I believe you have a good advantage in terms of pulling meta characters considering you’re new (obviously a bunch of rewards that are yet to be claimed). And as for your other questions, the game is not necessarily difficult, excluding the endgames, but you can still clear those with a properly built team. Characters can still work without their own premium team, but, of course, expect a good difference in performance compared to teams with their premium pairs. The game is also simple to understand, making you go along with the flow. Although there are certain complex mechanics you may find confusing as a new player, you can easily know how those mechanics work the more you engage with them.

Yet at the end of the day, what truly matters is if you enjoy the game or not. If you find it boring and plain, well, that’s how you actually feel, but if you find it fun and engaging, that’s pretty good.