Proofreading your own work without a significant time gap is pretty useless. You’ll catch a few obvious errors, but approaching the same problem in the same mental space tends to lead to the same thought patterns, tends to lead to making or overlooking the same mistakes.
You’ll do a bit better reapproaching the subject a few days later. It’s almost, but not quite, like reading a new piece of writing. In my experience, comments are set and forget, unless you’re obsessive like me and enjoy rereading your old shit.
By far the most effective proofreading, though, is an Editor. There’s a reason it’s a paid position for anyone who makes a living writing. A completely different person will read the text more as-is, without accidentally interpreting it how they INTENDED it to be written. This will catch far more errors, but isn’t really practical for shit posting in social media. The closest you’ll get is someone calling out a typo or grammatical error.
As long as the intent of the message is clear, it passes the bar for acceptable social media content. We’re not writing PhD theses, we’re just having fun discussions. We’re not writing a paper meant to be readable to someone independently, we’re engaging in dialogue and can easily ask the other person to clarify.
TL;DR high-level proofreading and error correcting isn’t really as viable on social media as it is formal writing, nor is it really necessary as long as the message received is the message intended.
That’s your only contribution? Cool. Objections duly noted.