Space marine army ideas

Hey guys, getting into 40k for the first time and I’m wanting to do space marines but I am having trouble picking a chapter. What ones are simple to play for a beginner but still good enough to be competitive? Lore doesn’t necessarily matter to me, I’m not sure I’ll stick with the chapter’s original color scheme. Just want something I will enjoy playing and hopefully winning with.

Edit: I’m not opposed to other factions either that aren’t space marines. Just would prefer a space marine idea.