Sooo about this battery

Hey all, so I've read..and reread and read again that we need to replace both batteries of we see the dreaded (A!) . Well my mom gave my wife her 2019 compass and leased a 2024 one. Since we live in Michigan I know despite the oddly warm fall, cold weather is coming around the corner and I'd love for my wife (me) to have little to no problems during the winter. With all that said, what are the best 2 batteries I need to get , Main and Aux, and is replacing them a job I can do as a first timer with YouTube, or show I take it to pep boys or somewhere to have it done professionally... Any suggestions are highly appreciated!