iMac 27'' (late 2013) in restarting loop

Hi everyone,

I have an iMac 27” late 2013 and two weeks ago its kept restarting continuously and it’s a message that is a problem with the machine, I think is called restarting loop. I tried to go in recovery mode, but the loading bar froze at the half way. I tried every key combination that I could find on Google or from Apple support chat(messages) and not any luck. I should mention that 6 months ago I replaced the original hard disk with Samsung 860 evo 2TB SSD with no issues. Also, the iMac has 32GB RAM.

I removed the SSD from iMac and connected to MacBook Pro (late 2015) through usb -sata cable to boot and access my files. I could see the SSD in Finder and all my data but is not booting. Actually, the first time when I connected the SSD to MacBook Pro I could boot but it froze at the half way and after that not able to boot again. After I saved all my files manually I formatted the SSD as APFS, downloaded Catalina, but it says that Catalina installer is too old for the macOS running currently. I went to Genius Bar for help, but they didn’t manage to find the issue. They help me to download Catalina from them system but when trying to make the external SSD (of iMac) bootable using terminal, an error when erasing the SSD. I used disk utility to format the SSD as Mac OS Extended (Journaled), I carefully enter the data on terminal, I change myvolume with the SSD name and the same issue. The Apple support said might be an issue with the SSD. Back home I tried everything again, I also put back the original hard drive into iMac and is not booting either. Now I bought a new SSD (the same brand) but I am afraid I will get the same results. I do not know what to do now, do you have any suggestions that I could try? Could be a hardware issue? Is the iMac too old to run again?

Thank you.