There have always been passport checks for channel crossings. Delays are nothing to do with Brexit.
There have also always been delays. Bad weather, surge in crossings and poor infrastructure.
Add into the mix French bloody-mindedness …..
Not Brexit https://www.express.co.uk/news/uk/1755889/dover-bank-holiday-traffic-chaos-france
🐦🔗: https://n.respublicae.eu/benhabib6/status/1644276018742476801