SharePoint list form JSON: "enabled": false / "readOnly": true - does not make field read-only (field still editable)

Target SharePoint environment

SharePoint Online

What SharePoint development model, framework, SDK or API is this about?

Declarative list formatting

Developer environment

None

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

No response

Describe the bug / error

Hi,
I am experiencing an issue with SharePoint list form customization using JSON. A field configured as disabled ("enabled": false / "readOnly": true) is still editable in the form UI.

Environment:
SharePoint Online
List form customization using JSON (Configure layout)
Standard SharePoint form (no SPFx extension)

Problem description:
I am trying to make the field CzynnoscRW read-only (disabled) using fieldSettings. However, despite setting "enabled": false / "readOnly": true, the field remains editable in the form.

JSON configuration used:
{
"sections": [
{
"displayname": "Szczegóły zadania",
"fields": [
"SzczegolyZadania",
"Miejsce",
"MiejsceKomasacja",
"MiejsceZwrot",
"Czynnosc",
"CzynnoscRW",
"CzynnoscWydanie",
"Dok"
]
},
{
"sections": [{}],
"fieldSettings": [
{
"name": "CzynnoscRW",
"enabled": false
}
]
}
]
}

Steps to reproduce

Open SharePoint list
Go to Configure layout → Body
Apply the above JSON
Open item form (New/Edit)
Try to edit CzynnoscRW

Expected behavior

Expected behavior:
The field CzynnoscRW should be disabled (read-only) and not editable.

Actual behavior:
The field is still editable.