A modpack is essentially a collection of many mods, designed to create a specific theme and mechanics for the game. Although there is no official RLCraft for Minecraft Bedrock, you can still individually install most of the mods' Bedrock edition and create an experience very similar to RLCraft. It won't be the same and you might not be able to play it with your friends unless they also go through the same process. But it is still possible. There's a good Reddit thread about it explaining and linking to the mods you'll need. I'd personally suggest just getting the Java edition.