How to check what type of DNS server is set up on my machine by default? (DNS-over-HTTPS, DNS-over-TLS, other?)

The normal DNS services used by the OS (regardless whether that is Windows, MacOS or Linux) are the plain DNS services.
In order to use any of the more advanced DNS variants additional configuration and, in most cases, additional software is needed.
E.g. on Windows Microsofts own DNS client doesn't understand any of the newer variant. You need to install an alternative DNS client that can use them.

Your computer knows what DNS service(s) to use because you either configured that manually or because the computer was given that information by the DHCP (which in a home-setup is usually provided by the router).

Considering the 2 DNS addresses you mentioned:
The first one is registered to Multimedia Poland and the 2nd one to VectraNet in Poland. Both are associated with the Polish ISP Vectra.
So I presume that Vectra is your Internet Provider, they have provided your router and its DHCP is configured to instruct your computers to use their own DNS servers.