[CONSTANT CRASHES] New champion select frequently crashes game

Hi there, I emailed support about this and they told me to post on the forums instead. Since the last patch, the new champion select in normal/ranked draft has been frequently freezing or lagging out. These are two different bugs with differing circumstances. Either one of these bugs now occur roughly 30-50% of the time--this has prevented me from being able to do any ranked games in fear of my game freezing. I'm already at a negative LP as a result.

FREEZING:

• at any point in the champion select process, when the champion window opens or closes the entire game window may instantly freeze. Given that this has happened nearly a dozen times, I think I've narrowed down that it only happens when the champion window is opening or closing. This can be 1 second into champion select when it opens for pick intent, or it could happen as late as 5 seconds until the game starts during the trade phase. It seems to always happen when the champion list window is opening or closing though
• 100% leads to game freezing and having to close the process.
• If I've locked my champion in already, I can wait long enough for the game to start and then close the process so it doesn't count as a dodge.
• If I haven't locked in my champion or ban, the game will dodge once it gets to my turn

LAGGING OUT

• Basically, the champion select process lags out and everyone's selections remain frozen. for example, if it is opponent 4's turn to ban and the game freezes about 2 seconds in before they've nominated a champion, the clock will count down to zero and simply stop there. It will remain that way for me even if in reality they made their picks.
• I can still type in chat and other players can respond to me in real-time while it's lagged out. Other players are not affected by this. This is how I know the game is not frozen.
• this can occur at any point in the champion select process. I do not know what triggers it.
• Twice it has unfrozen just in time for me to lock in my champion, although it did not unfreeze for 3-4 minutes. In these cases I had either already banned a champion or was simply later in the pick phase.
• Almost always the match would be dodged because it would get to my turn in the pick/ban phase. For me, I wouldn't even know it's my turn because it still appeared to be frozen wherever the process was before.

Extra Information:

• These issues became extremely frequent in patch 6.4
• My internet connection is stellar and I have a consistent 30 ms internet connection.
• My PC is top-of-the-line.
• I've ran the client repair more than once in the last patch alone and it has not solved this problem.
• There are zero third-party-programs related to LoL on my computer.

Both ranked and the new draft mode are essentially unplayable at this point because of the frequent crashes leading to dodges. Although my match history does show a lot of draft mode games in recent days, I've had to stop playing ranked entirely since these problems began in patch 6.4. Also, many times I'm lucky enough that the freezing/lagging out/crashing happens after I've already locked in my champion--thus allowing me to start the game without dodging. In many of my games, this is what happened.

I've seen others post on the forums about precisely these same problems. I hope there's something I can do to fix them, because I'm not even sure if they're on Riots radar...