File Explorer for one - Windows 10's is a mess of unfinished "great" ideas and generally looks like the product of 1000 monkeys randomly typing things in Visual Studio... Windows 7's is far better other than missing the newer file copy dialogues and they never fixed the file deletion refresh bug.
You will not rely on Windows 7 soon when Nvidia will drop Windows 7 driver support in October 2021 then internet browsers will drop Windows 7 support in January 2022 and anti-virus/internet security software will drop Windows 7 support in July 2022 that will leave Windows 7 full exposed to hackers, ransomwares and viruses. Sadly, you obviously learnt nothing from Sony Pictures hacked and WannaCry ransomware.
That isn't exactly a good thing and doesn't make Windows 10 any less bad for when you need to rely on an OS for some tasks.
Sony attack used phished credentials to log into the Sony Network and deploy a dropper crafted to exploit the network with hardcoded address and credentials - it wasn't specifically a Windows 7 problem - they were already inside the network.
WannaCry despite some headlines about Windows 7 wasn't actually a Windows 7 issue as such - in many cases they exploited a bug in the Windows 10 malware protection engine to actually make it execute the dropper which was the first entry point to many networks, in other cases they exploited where networks had SMB exposed to the world which wasn't necessarily a Windows 7 machine. The main cause of the issue there was vulnerabilities in the SMB protocol.
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2017-11937
No he didnt get mixed up with Windows 10, he talked about Windows 7! All Windows versions is plagued by security issues and loop holes, since Windows 7 end of life support back in January 2020, Windows 7 is plagued with 560 security issues and loop holes included 63 very serious issues that cant be updated and patched. Since May 2021 it had 15x privilege escalation and 15x remote code execution. Both Windows 8.1 and 10 has same issues.
https://www.cvedetails.com/vulnerab...&sha=47d29bad4e41fa72927e93dbd6b6e2cbeefa4e07
I'm not holding up Windows 7 as a superior security options far from it - but if someone really cares about security 10 is a never end source of new exploits, many of which should never have existed in the first place, often aren't due to legacy code existing in previous OSes and in some cases were being actively exploited. Given how often new serious vulnerabilities are found with 10 many of which should not exist in the first place it is likely there are many more to come yet. The only advantage there is 10 having more active support for closing these vulnerabilities but that doesn't help much if a new one is exploited before it is closed.