Client and Crash

I have this issue with low priority and crashing. I may have this issue because I own a pretty old and low performing PC, but League loads fast when not on low priority but...

I got low priority one time and waited the 20 minutes, got into champ select etc. But getting into the loading screen took 1 minute or two because a black screen would fill it and after waiting everyone in the game would load faster than me when I’m like at 40% load. And eventually my team remade even though I was waiting for my game patiently. Leaving the game... Leaverbuster gave me another 5 queues of low priority because apparently I “left” and it’s happened ever since and I can only find solace and actual loading in Co Op VS AI.

I just want to be free of 20 minute queues...