In VSCode there is the option "typescript.reportStyleChecksAsWarnings": true. This changes some common errors reported by typescript to be shown in the editor as a warning:
https://github.com/Microsoft/vscode-docs/blob/main/docs/typescript/typescript-compiling.md#why-are-some-errors-reported-as-warnings

Here is where the specific errors to convert to warnings are defined:
https://github.com/microsoft/vscode/blob/c1c103dee729b6f702c1c5272d25b24ea9664d48/extensions/typescript-language-features/src/typeScriptServiceClientHost.ts#L38-L46

It would be nice to have this in typescript-language-server as well because when I develop with errors being reported as I type, and the errors that are converted by reportStyleCheckAsWarnings are errors that I generally don't care about until I finish a segment of code. But those errors tend to drown out the more serious errors. By showing those errors as warnings instead they could be filtered by the editor to display them differently (e.g. with a yellow line instead of red line).