From what I’ve seen, you need to invest a lot of time and effort into creating a relationship with your audience of whatever social media platform you choose. This doesn’t come easily to many people, understanding your audience and getting people interacting with you is hard work!
Facebook has 1.86 billion monthly active users, so it has to streamline what posts get seen and by whom, so they use algorithms. I know that with the pages I have “liked”, I don’t always see their posts because FB assumes if I haven’t interacted in a certain period of time with the posts on that page, then I’m not actually interested, so will hide it. Based on my previous interaction history, it decides what to show me. This is why trading "likes for likes’ or similar can actually damage reach, because those people very rarely come back and actually interact with your page afterwards. Want you want are genuine people who are interested not in just what you do, but you and your brand. I don’t think anyone likes just to see “listing” and “for sale in my shop” posts.
I sympathise, it is hard, I haven’t cracked it because I just don’t spend enough time on it consistently, and even less now since I started working full time last autumn.