Database query filtering in ASP.Net core web api

I am creating a web API in ASP.net core for my angular frontend and right now I have implemented a filtering feature on my frontend page where the users can filter and sort the data using any field, with regex filters, and also allow the user to only show a number of elements on each page. the problem with this is that: every time I have to send all the data from my backend which won’t come in handy when I have a big database, so I must do the filtering, ordering, and paging on my backend depending on what the user requested from the front.
How’s this problem usually solved? are there known technics for doing this?

Is it possible to connect an existing local Database in Visual studio and generate the Data on Web with ASP.NET mvc Core?

I am currently learning Asp.net core Mvc (with vs 2019) and I have a question. I know I can create a model and with help of Scaffold create a local database through the program but I if I have already my own sample database, how I can insert it and show some details to web?
I’ve read about .Net framework and ADO.NET Entity Framework but this isnt working on Core version.
Followed Microsoft guides but they had only the “Seed Data” but i can’t make it work with my db Table.
Is there any way I can achive it? Or i have to recreate the project on .Net Framework ?