Can't Edit Text on Live Website

Hi everyone,
I’ve been facing this issue for a few months now. I’m trying to update the text on my website and every time I am on the designer and click into the text box, it is really finicky. It’ll delete whole lines, won’t let me add more text etc.

More frustratingly, whatever I manage to eventually edit and attempt to publish, it doesn’t actually reflect on the live site.

Any way to get around this?