Your content should be engaging each audiences attention on each platform. Otherwise you’ll never be able to have a real conversation with your followers.
Each platform has its own feel and vibe. Knowing what and how your audience is searching on these platforms will dictate what content you distribute to the platform. I remember going to my Grandparents and hearing the same story over and over, I was raised in the south so I was taught to ALWAYS respect my elders, so I would listen like it was the first time I had heard it but imagine being at work and someone tells you a story, then on the way home you hear the same story on the radio, then again at home on the tv, then when you open the book you are reading and the same story is there…get the idea. People engage with the social platforms at different places and times in their day and if they hear the exact same thing from you, they will turn you off.
Think of Facebook/Instagram as you were hanging out with your friends socially, Youtube as either entertainment or informative. Linkedin would be a time to share business success and other professional information. You also need to consider the demographics on each platform. Linkedin has slightly more men than women, and mostly over 30. Instagram has more women than men, and mostly under 30. Most likely, the same person that follows you on Instagram will not on Twitter.
I understand posting consistent content is already hard for small business dealing with all the other things that need attention throughout the day. One technique to help with this task is multi purposing content. Create one long piece of content and break it it smaller pieces of content to distribute for each platform.
You can shoot a 10-15 min video on how to do something in your business, use the audio for a podcast, have the audio transcribed for long text post, pull out smaller :60 clips that are strong and use those for Instagram, use the transcribed audio to make visual posts with graphic overlays.
Even small tweaks to copy, photos or layout is enough to engage with your audience on the different platforms.