If you trust Microsoft and the US Government with your private keys then by all means use Windows 10. I use GNU/Linux and I must say that I trust the US Government way more than many on this forum.
As for staying with Windows 7, why keep fighting change? The direction that Microsoft is heading in has been very clear for a very long time. I moved to GNU/Linux back in 2006 since at the time I did not like the "vista" on the horizon.
I switched to GNU/linux back in 2009. The only problem for me arose when I bought an HP laptop. It has been a pain in the ass only to install Ubuntu due to UEFI restrictions. After I installed everything, wifi and video card would not work properly and I had to go back to win 8.1
I also tried manjaro linux (based on Arch) and opensuse but nothing changed.
Do you know any good laptop which are fully compatible with linux nowadays?
The first thing to understand about buying a laptop from a vendor such as HP is that there are basically two kinds of laptops. Those sold to consumers and students which are basically junk that is engineered to fail in about 6 months, and those sold to businesses that are quality products designed to last for a long time. It is important to realize that the same manufacturers are selling both the junk and the quality products. The simple way to tell them apart is that the consumer versions come with a glossy high glare screen and the "standard" "home" or "personal" versions of Windows while the business versions come with a matt anti glare screen and the "pro" or "business versions of Windows. So "HP Laptop" is meaningless depending on whether it is consumer or business it is either a piece of junk or a quality product.
The option for a GNU/Linux laptop are several depending on budget.
1) Purchase a Laptop that is designed from the ground up to run GNU/Linux
Here are some examples:
https://puri.sm/ This in an over subscribed crowd funding campaign for a Laptop designed for 100% Libre GNU/linux distributions. This by the way ensures it will work with virtually any modern GNU/linux distribution.
https://system76.com/zareason.com/etc.
2) Purchase an older (Windows 7 era) business laptop, and upgrade the hard drive to large SSD and possibly also the RAM. Before buying check online if that particular model has any driver issues with GNU/Linux. One thing to keep in mind is that if it is two or there years old and there little or no hits on the fora then it is likely to have few if any problems. Also when it comes to drivers GNU/Linux is very good at supporting hardware typically after about 2 years so something that failed say in 2013 could very easily work fine today. I recently bought two HP 2760p EliteBooks from a government auction for well under 200 CAD each. After adding a 1 TB SSD each and upgrading the RAM on one to 16 GB and the other to 8 GB I have two quality laptops that will last me a long time. One of them replaced an HP Evo 1000c with a Windows 2000 logo and 3.5in floppy drive that provided me with close to a decade of service. When I replaced it this summer it was running a full Bitcoin node using Trisquel GNU/linux. By the way UEFI should not be a problem if it is unlocked (Windows 8.x and earlier). Just go into the bios and unlock it. If it is a Windows 10 machine it may be locked. I suspect that most of the locked Windows 10 laptops will be sold to consumers as part of Microsoft and its partners ongoing junk for consumers program.
3) Buy a Chromebook and upgrade the hard drive. Chromebooks are good GNU/Linux computers except that they have ridiculously small hard drives. They have to be sold unlocked because Chrome OS contains GPLv3 code.
