My MacBook Pro automatically restarts few times before it finally opens

It is a GPU and/or Display issue. I've never seen that one first hand though. I have seen these Intel USB-C laptops reboot if the battery charge is 0%-1%.

Try booting into Safe Mode to see if that works.

FYI, the Logic Boards for these 2018-2020 Intel Macs tend to have a higher rate of failure than older models. I guess you could try a DFU firmware Revive to reset the T2 security chip & system firmware to see if that makes any difference....doubtful. While a DFU firmware Revive should not affect the data on the internal SSD, I would highly recommend have a good backup just to be safe since I don't know what would happen if the Revive process failed.

You can also try running the Apple Diagnostics to see if any hardware issues are detected. Unfortunately the diagnostics rarely find any issues even when a hardware issue is confirmed through other methods, but it doesn't hurt to try since any failure would confirm a hardware issue.

That is the same Problem i have also. I am looking for help but i believe than apple ifselfes don't know what is to do.