I have heard a lot of complaints about lack of editor integration or flaky editor tooling in the Reason community. At my previous job we had ~3000 modules and ~80k LOC. I'll admit that we were not very vigilant with .rei files or keeping our inter module dependencies really clean so this slowed both bsb and especially reason-language-server down a lot.
In fact so much that people couldn't use reason-language-server anymore on 15" MacBook Pros.
I myself have always used a Merlin based setup since I joined the Reason eco system before reason-language-server, and in our project my setup had never failed. Therefor I went on a quest of setting up 3 of the major editors (Emacs, Vim and VSCode) and documenting how to get them working