Sample column formatting to display as many choices as Max. Reference:https://github.com/pnp/List-Formatting/tree/master/column-samples/multi-choice-bulleted-numbered-list

multi-choice-bulleted-list-max.json

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "children": [
    {
      "elmType": "div",
      "style": {
        "display": "flex",
        "flex-direction": "column",
        "justify-content": "flex-start",
        "flex-wrap": "wrap",
        "margin": "5px 0px"
      },
      "children": [
        {
          "elmType": "div",
          "forEach": "choiceIterator in @currentField",
          "style": {
            "margin": "3px 0px",
            "display": "=if(loopIndex('choiceIterator')+1<=[$Max],'flex','none')",
            "flex-direction": "row",
            "align-items": "center"
          },
          "children": [
            {
              "elmType": "div",
              "style": {
                "margin-right": "5px"
              },
              "attributes": {
                "iconName": "FavoriteStarFill"
              }
            },
            {
              "elmType": "div",
              "txtContent": "[$choiceIterator]"
            }
          ]
        }
      ]
    }
  ]
}