Color settings for dimming type annotations in VSCode, change "foreground" as you wish

vscode-types-settings.json

{
  "editor.semanticHighlighting.enabled": false,
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "scope": [
          "support.type.primitive.ts",
          "entity.name.type.ts",
          "meta.type.tuple.ts",
          "meta.type.annotation.ts",
          "meta.type.parameters.ts",
          "keyword.operator.type.ts",
          "meta.return.type.arrow.ts",
          "keyword.operator.type.annotation.ts",
          "meta.return.type.ts",
          "support.type.builtin.ts",
          "punctuation.definition.typeparameters.begin.ts",
          "punctuation.definition.typeparameters.end.ts",
          "keyword.control.as.ts",
          "meta.object.type.ts",
          "meta.object.type.ts punctuation.terminator.statement.ts",
          "meta.object.type.ts punctuation.definition.block.ts",
          "meta.object.type.ts keyword.operator.optional.ts",
          "meta.type.parameters.ts storage.modifier.ts",
          "meta.type.parameters.ts punctuation.accessor.ts",
          "meta.type.declaration.ts punctuation.accessor.ts",
          "meta.type.parameters.ts punctuation.separator.comma.ts",
          "entity.name.type.module.ts",
          "meta.object.type.ts variable.parameter.ts"
        ],
        "settings": {
          "foreground": "#616E88"
        }
      },
      {
        "scope": [
          "support.type.primitive.tsx",
          "entity.name.type.tsx",
          "meta.type.tuple.tsx",
          "meta.type.annotation.tsx",
          "meta.type.parameters.tsx",
          "keyword.operator.type.tsx",
          "meta.return.type.arrow.tsx",
          "keyword.operator.type.annotation.tsx",
          "meta.return.type.tsx",
          "support.type.builtin.tsx",
          "punctuation.definition.typeparameters.begin.tsx",
          "punctuation.definition.typeparameters.end.tsx",
          "keyword.control.as.tsx",
          "meta.object.type.tsx",
          "meta.object.type.tsx punctuation.terminator.statement.tsx",
          "meta.object.type.tsx punctuation.definition.block.tsx",
          "meta.object.type.tsx keyword.operator.optional.tsx",
          "meta.type.parameters.tsx storage.modifier.tsx",
          "meta.type.parameters.tsx punctuation.accessor.tsx",
          "meta.type.declaration.tsx punctuation.accessor.tsx",
          "meta.type.parameters.tsx punctuation.separator.comma.tsx",
          "entity.name.type.module.tsx",
          "meta.object.type.tsx variable.parameter.tsx"
        ],
        "settings": {
          "foreground": "#616E88"
        }
      }
    ]
  }
}