Posting for visibility - having the same issue. Last season, my game froze regularly during the countdown right before character select. The workaround I used during last season, alt-tabbing out whil the game was launching and alt-tab back in once the team/champion squad screen appeared worked then (still weird, but worked).
Since the update, same as you guys - game freeze usually within a minute of landing. The longest game I've had this season was 6 minutes until it froze, couldn't play a single game through to the end.
Saddest thing is that there doesn't seem to be any response whatsoever from Respawn. Guess this is it for me for the time being (started playing in week 2 after the game released). Will keep an eye out if there's any more fixes I can try (tried all that have been mentioned here by other community members) and hope that if enough people have the same problem, Respawn will look into it.