I need help with Adobe Premiere Elements 2023. When I make a portrait video for social media and add subtitles, they look squashed compared to the landscape version. Why?

Your project settings are set up for a wider than tall aspect ratio (16:9) video. 

Are there regular 16:9 videos already on the timeline? There’s no way to have more than one project set-up in your movie. Your video project can be taller than wide or wider than tall but not a mix.

Can you post a screen shot of your timeine so we can confirm this?

You posted in the Premiere forum, not the Premiere Elements forum.
I requested a moderator move this to the proper forum.