flitter not found

[bitWest11]

west@pop-os:~/flitter$ dune build File "src/dune", line 5, characters 27-40: 5 | (preprocess (pps lwt_ppx ppx_sexp_conv)) ^^^^^^^^^^^^^ Error: Library "ppx_sexp_conv" not found. Hint: try: dune external-lib-deps --missing @@default

however,

west@pop-os:~$ opam install dune core lwt re color sexp_pretty uutf lwt_ppx uuseg notty [NOTE] Package notty is already installed (current version is 0.2.2). [NOTE] Package uuseg is already installed (current version is 15.0.0). [NOTE] Package lwt_ppx is already installed (current version is 2.0.1). [NOTE] Package uutf is already installed (current version is 1.0.3). [NOTE] Package sexp_pretty is already installed (current version is v0.12.0). [NOTE] Package color is already installed (current version is 0.2.0). [NOTE] Package re is already installed (current version is 1.10.4). [NOTE] Package lwt is already installed (current version is 5.5.0). [NOTE] Package core is already installed (current version is v0.12.4). [NOTE] Package dune is already installed (current version is 3.7.0).

no package called external-lib-deps is available, and installing depext leaves me with nothing

west@pop-os:~$ opam install depext [ERROR] depext unmet availability conditions, e.g. 'opam-version >= "2.0.0~beta5" & opam-version < "2.1"'

[bitWest11]

so following the instruction from https://github.com/pizzart/blitter/tree/readme-plus i did manage to finish building it, however west@pop-os:~/flitter$ flitter Command 'flitter' not found, did you mean: command 'flutter' from snap flutter (0+git.ccbc698) See 'snap info ' for additional versions. it just doesn't work now for some reason.

[NullaOnion]

(I AM USING MANJARO)The only work around for this I found was running the command "eval $(opam config env)" in terminal before trying to open your split file with flitter. I needed to do this everytime I wanted to run it after closing the terminal though.