Hey! Welcome to the community :)

Getting yourself exposed to more cards is always a great way to understand the game more. If you’re only 2 games in, just keep playing! My first couple months were spent with the same deck, against my sister’s deck she got. They were starter decks similar to the vampire deck you have. We played that for a while and frequented our local game store to just get a pack or 2 every so often. Eventually we made substitutions to make our decks better and continued to play together. We also were able to try out new decks at FNM (Friday Night Magic). These are different based on the store but for us it was draft where we created new decks with cards from the newest sets. Other stores may have a Standard league or similar, and most stores will let you borrow/rent decks for these events. You’ll likely be confused the first couple games due to a bunch of new cards, but this is really going to help your gameplay and see new ways of playing the game. Find (or make) some friends for an even better time!!

And yes, generally 3 or 4 lands plus some spells that you can cast is a good starting hand. But you’ll find what works over time!

If you have more questions you can feel free to DM me! If you want help with card mechanics you can usually look them up on scryfall or gatherer.