The correct way to get someone to move to FOSS is to show them how to do it, not tell them it exists. OP already said they can do the YouTube -> captioned gif in 10min so you need to provide a simple tutorial that identifies the tools to use, how to set them up, and how to create a workflow to achieve the goal of some format with captions in under 10min.
Notice how I explained what was wrong and how to do it? That’s what’s missing from most “you need to use FOSS” posts, including yours.