As I said, 7 amber blinks isn't documented so that's not going to help. Do a BIST test on the PSU. Follow instructions here for PCs with only a PSU LED on back, but without a BIST test button. Assuming it passes the BIST, try clearing BIOS: If that doesn't help, and because this PC model doesn't support onboard Intel UHD Graphics, you would have to swap in a different PCI-e x16 video card to see if your video card failed. That assumes you can borrow one from another PC for this test. New video cards are quite expensive right now and there's no guarantee that will solve the problem, so I'd hate to see you spend money and still have the same problem.
I have a Dell Inspiron G5 5090 desktop (warranty expired December 2020) and a Dell S3222DGM monitor. A month or two ago my pc would crash and loud static would play in my errors this would be fixed with a restart, it happened more frequently so i went to dell updates and scanned my files and hardware, no issues where found. eventually this was happening every few minutes untill my pc stopped turning on, when i powered it up the power button was orange and blinked 7 times then stopped. I found a solution of turning my monitor on right after i power up my pc. this stopped working and now my pc will turn on and be lit up but my monitor says no signal found, i switched from a hdmi cable to a dp and still it won’t work. I also have a second monitor and it will not work for that ethier.  
Inspiron G5 5090, wouldn’t turn on now won’t display