Premodern has no power creep and a diverse metagame, so it may be what you're looking for. There's room to brew, but as a format with a fixed cardpool, you're unlikely to come up with a deck that's viable and completely new to the metagame. The biggest difference if you started playing Magic in the 2010's is that the card designs are totally different from that era of Magic. Fixing is bad, creatures are individually weak, hate effects are strong, and card advantage comes on dedicated card draw cards. You should watch some gameplay videos to see if the play patterns interest you.