Note 9 N960F/DS bootloop

Hi I am using Note 9 N960F/DS

I flash TWRP recovery

Then I flash only BL of combination ROM

Then I get Recovery image signature check fail!!!!!!
Reboot to avoid warranty bit set!!!

And

Boot image signature check fail!!!!!!
Reboot to avoid warranty bit set!!!

Could not boot my phone due to this bootloop.

I go to download mode and flash a up_param which maybe can be corrupted

Then now I cant go to download mode anymore

And I get bootloop on white screen.

My phone was running

N960FXXU2ARL3 before this.

When I try to enter download mode I am stuck on black screen, and phone wont switch on then until I hold the power button for long time

PC does not detect the phone

Will a micro USB download mode jig cable work to force USB C Samsungs into download mode if they bootloop?

How do I get out of this? Thank you all..

Picture are here: https://imgur.com/a/67OFzHQ