How do you keep up with all the changes in social media algorithms?

Short answer: you don't.

For the long answer, watch this 1-minute video:

Best Times to Post on Social Media: Rules vs Principles vs Reality

There is no "best time to post" on any social media.

Any study that claims to reveal the perfect time to post on any social media platform is, instead, revealing the mathematical results of an algorithm they used to calculate certain (possibly beneficial) outcomes at one particular moment in time, for some general group of posters.

No one can possibly tell you when the bulk of your followers and potential followers will be ready to receive your message. There is no calculation to allow one post to be carefully planned to accomplish more than some other post.

Here's what works: consistent persistent personal relevant content.

Always has. Always will. No trickery or algorithms needed.

Update

An article by the social media management tool company Buffer makes the same point with more specifics.