Hi, welcome to the game
Of course, that Regnum is far from perfect - there are several bugs reported for years, but the game is still fun, and offers great aspects.
You mention a "pay to win system for levelling". I"m not quite sure, what you mean by that. While levelling up, you can buy xp scrolls, or scrolls that level you up. Personally, I never brought such items, and just grinded up the "hard" way. It takes longer, but it's free and possible. Therefore, buying such items that help you level only save you time.
The only real item you should purchase is a permanent mount - it really helps you to get around faster, which is useful while questing, and also important in the warzone. If you have access to a temporary mount, use it first to see, how the game will be for you, before investing money into it. I wouldn't recommend you to buy any gear with real money, before you reach the warzone, since at low levels you change your equipment fairly often.
Anyway, It's great that you're having a good time, and if you need any help, don't hesitate to ask in realm chat, or on the forums.
Regards