I'll preface this with three things. 1. I prefer schemes over Common Lisps, and I prefer Racket of the Schemes. 2. There is more to it than the points I raise here. 3. I assume you have no previous experience with Lisp, and don't have a preference for Schemes over Common Lisp. With all that out of the way... I would say Common Lisp/SBCL. Let me explain
- SBCL Is by far the most common of the CL implementations in 2021. It will be the easiest to find help for, easiest to find videos about, and many major open source CL projects are written using SBCL
- Download a binary directly from the website http://www.sbcl.org/platform-table.html (even for M1 macs) to get up and running (easy to get started)
- Great video for setting up Emacs + Slime + Quick Lisp https://www.youtube.com/watch?v=VnWVu8VVDbI
Now as to why Common Lisp over Scheme