Eurostar say leisure travel is back to 100% of pre-pandemic levels & business travel 80-85%. But due to Brexit they can only provide 70% of pre-pandemic capacity. They've plans to resolve this including trialling online check-in, I've added a summary at https://www.seat61.com/news.htm
The Man in Seat 61:  What's new on the site

News page on the Man in Seat 61 website

@seatsixtyone Why don't they just reopen Ebbsfleet and Ashford? If the bottleneck is st Pancras, adding two more stations in the UK would increase how many seats they could sell, Surely?
@quixoticgeek @seatsixtyone
Staffing two more sets of check-in, security, & border formalities.
@slideman @seatsixtyone paid for by selling 30% more seats ...
@quixoticgeek @seatsixtyone
I guess govt has to fund the border formalities, but €* gets the seat money.