How expensive is Beijing between May 7th and May 11th? Asking because of labour holiday

Hello I’m planning on visiting my boyfriend studying in South Korea for semester abroad and will have 18 days free.

I have planned to stay for 11 full days in Korea (5 days in Seoul and the rest travelling around other cities/countryside) and it might be enough for me there. Since all affordable flights to my home country go through Beijing, I was thinking about spending the last few days of my holiday there. It would be from May 7th to May 11th.

And that’s where the problem lies - I read that May 1st to May 5th is the most expensive time to visit Beijing because of the labour day holiday. I expect many people are extending their trips and prices are going to be steep.

So I want to ask - how bad is it when it comes to prices and crowds during this time?

Thank you!

To add: staying the whole time in Korea is not a very good option for me as plane tickets would be a lot more expensive and my boyfriend would not have time for me for the last few days.