I am unable to login at my pc after least update on stable kde neon

I am a kde neon user for last 6 months
Today I updated my system from my package manager, but after update it wants a restart, after restart it took me in it’s default login screen, not my regular custom login screen . But when I try to login my account it accepts the password and than show black loading screen but after 2 sec it brings back the login screen again. but if I input wrong password it says wrong password.
But I am able to access my account in virtual terminal.
What should I do now?

Log into a tty (as you already successfully did) and try sudo pkcon refresh && sudo pkcon get-updates .
If there are any packages try sudo pkcon update and reboot .

Otherwise you could try if something mentioned in Plasma 6 update, desktop won’t load helps - like autoremove and reinstall…

Sorry for my late reply.
After running that it gives a error

And foram link you shared ,there was alsosome one who got exactly same problem what I got.: Plasma 6 update, desktop won't load - #5 by jtowns

But the solution was : Plasma 6 update, desktop won't load - #16 by Herve_Lefebvre

But it didn’t solved mine. I got thi problem like here: Plasma 6 update, desktop won't load - #40 by Helium

Thanks for your support.