Whenever I click on the 'PLAY' button on the home page for Java Edition in the launcher, the loading bar shows and starts loading and as soon as it reaches the end, the launcher closes and then a few seconds later reopens and shows the message
"ERROR Game crashed
An unexpected issue occurred and the game has crashed. We're sorry for the inconvenience.
Exit Code: -1"
as given in the first screenshot.

Moreover, a lot of the times when I open the launcher it shows a message in the top right: "Sorry! We were unable to get your account information. Please restart your launcher." 
and in the bottom left:
"Oh no! Something went wrong, and you will not be logged in automatically next session."
as given in the second screenshot.
After redownloading the launcher when I click on play it starts downloading and then shows 0/66 MB downloaded and when that is finished, the launcher closes, reopens, and shows the error message and exit code. I do remember having changed the priority of the minecraft.exe task to above normal using the task manager at one point but that had not caused problems previously. What I'm suspicious about is that the launcher downloads only 66 MB and then tries to launch the game. I am not able to access the launcher files as it is now a windows app. The previous launcher version used to work normally for me. These are my launcher logs:
launcher_cef_log.txt: https://paste.minecrafthelp.co.uk/?f3298e14bb886617#6pSb8s2vc9fhwq9uGV6yN2sY5E9fYuiCkuhUD4z8rjDY
launcher_log.txt: https://paste.minecrafthelp.co.uk/?7a61b1e2eaeb79c1#CWDGdyJotuy79UDP94FqZqokzxAauKgDtDnsafkVaPjT