Can I ask what you mean by CLISP being dead? The last stable release was 10y ago yes, but development continues to this day and beta releases are available. Nixpkgs actually ships a beta version by default now.
I maintain a Nix scope with hundreds of Common Lisp packages and I am actually about to merge a dev branch that introduces CLISP support for all packages & their tests; it holds its own pretty well: https://github.com/hraban/cl-nix-lite/tree/clisp. see the list of all packages in the lisp-packages-lite.nix file).
CLISP development: https://gitlab.com/gnu-clisp/clisp
What errors do you get? ABCL successfully runs Serapeum’s full test suite on my machine (aarch64-darwin).