I used to write one post and paste it into five platforms. Four of them did nothing and I blamed the algorithms.
The algorithms were not it. One piece of writing was doing work for five different reading situations. A forum reader is scanning to find out whether your problem is their problem. A feed reader is scanning for a reason to stop moving. Those want different first lines even when the idea underneath is identical.
Two things changed it.
Cut down, never pad up. I write the idea once at full honest length, then every platform gets a cut. The short ones get the sharpest 40 words instead of a paragraph amputated at the limit.
Rewrite the opening for each place. That is the part most people read, so it is the part that has to be native to where it lands. The middle travels fine.
A quick way to check which one you are doing: try pasting the post somewhere else with no edits. If it fits perfectly, that usually means it was written for no particular audience rather than for both.