Problems with Adobe Reader… want to use Preview

A few months ago ( I don't really know the exact date ) all my online pdf's open in Adobe Reader and it is horrible to use. I cannot scroll smoothly and it defaults to a large magnification.

It also wants me to "trust" each new pdf.

I thought my default used to be Preview.

I don't know if I missed a change or what.

I tried uninstalling Adobe Reader but then I couldn't read any online pdf's.

I am looking to be able to use Preview again for my online pdf"s.

I tried saving the file as a Preview file but it gives me an error and says the file is empty 😟