need help! installing new GPU and lot of problem occurs

pc spec before updating

ryzen 5 3600 asus rog strix b450f 16gb ram @3200mhz geforce GT 730 250 gb ssd monitor : benq zowie xl2540

it was running fine no problem at all,only once got bsod

and then several days ago i bought gtx1650 super zotac brand

i put it in to replace gt730 and connect the 6 pin power cable to the gpu that i have previously prepared when i started building this computer in october (the cable was just sitting there the whole time because the gt730 dont need a power cable)

and then i install the drivers without cleaning the previous (the previous driver was through windows update,because i cant find gt730 driver in nvidia website),it all run smoothly,but sometimes i will suddenly having this weird problem,like suddenly my pc running so slowly,even doing alt tab is very slow,and i need to restart (even the restart process is going very slow) the pc to get it back running like normal again,this happened like once a day,then im using DDU,going into safe mode , wiped all my display drivers,and then reinstall the gtx1650 super driver again,its still the same,sometimes i still get that slowing /lagging issue

but today it got worse,my screen is literally broken when i opened csgo,at first it only started blinking in the lower bottom half , after i opened csgo,whole screen is broken,im trying to restart into safe mode,screen was okay,no tearing/broken pixel etc,i used ddu again,going into windows again screen was okay,once i reinstall the driver,the tearing come back

i decided to reinstall windows,after windows finished installing,im having black screen during windows when im downloading software etc ,i cant get it back,it just completely black,try to restart,but i cant boot into windows

i pulled out the gtx1650s,put the gt730 back in

im able to write this because im using gt730,but i still have this blinking issue in the bottom part of the screen, like a camera flash ,if i press ctrl alt del, it will be nonstop flashing in bottom part,just like a hair wide flashing white in bottom of the screen

thing i havent done is trying to reinstall windows while using gt730 (the current windows was still installed using gtx1650s)

also my friend whos a pc expert,recomend me to update bios on my motherboard,since the gpu is new lately,and my motherboard bios latest update was in august.

i want an opinion,is the card i got faulty? do i need to update my motherboard bios? or is it my monitor?