My dog refuses to walk - what can I do?

Hi everyone, I have a Frenchie who is almost 2 years old (1 year and 11 months, to be exact). I’m having a bit of a nightmare at the moment; every time we go for a walk, whether it’s a quick stroll or a longer outing, she just refuses to budge and there’s nothing I can do. I’ve looked for advice online and I've even seen a dog behaviourist!

But nothing is working. I’ve tried to figure out if she’s scared or in pain, I’ve tried being really encouraging and even bringing a toy (though she couldn't care less about toys when we're outside!). I’ve also tried using treats but it’s no use, she just won't move...

Does anyone have any tips or advice they could give me?

Have a lovely day!!