Previous poster mentioned the basic stuff, I'll reply for the rest.
47 minutes ago, admkhalid said:
Question 2: Is there any way I can set up 1dot1dot1dot1.cloudflare-dns.com in my device settings (Windows/Ubuntu/Router) just like on Android? Or is the problem with my ISP?
Yes, you can, but you will need additional tools to be able to use DoH (DNS-over-HTTPS) or DoT (DNS-over-TLS), which are two methods of using encrypted DNS. Using an encrypted DNS means your ISP (and other parties inbetween) can not see and intercept (e.g. modify) your DNS requests. It's not a VPN, it just uses widely used protocols to encapsulate DNS requests in an encrypted packet.
Android (and I believe iOS as well) has built-in support on the OS level. Other operating systems do not have this built-in (yet, Windows has it in their Insider program atm) and you need to download other tools for that, e.g. Stubby, dnscrypt-proxy, dnsmasq or something else. Same applies to the routers - generally they don't have this feature, some newer ones might have it. Browsers have started to add encrypted DNS option, but that only applies to specific browser and not to other applications running on your computer.
As a side note/bonus read - DNS is not the whole story. Your ISP can still see which domains and IPs you connect to (or all your page visits in case of unencrypted browsing). They can still block based on these parameters. To prevent that, you'd have to use a VPN or some sort of proxy.