Nested blocks/layouts performance

[mynameisfreedom]

Description
Generally, I am aware that nested blocks and structured fields are performance heavier, but I think this should be on the list for improvements.

For better performance, I rewrote all my blocks and dropped out all nested fields/bocks and structured fields, but I can't remove one thing.

The layout field "grid" doesn't have the possibility for a subgrid inside columns, so I created a block with a Layout field, to accomplish a subgrid. Although this works ok, it slows the panel very much. Panel page with Layout Builder now opens 5 times slower and saves a page 10+ times slower.

Expected behavior
It is understandable that nesting fields will be slower, but not to that extreme extent.

To reproduce

1. Create a Layout field with fieldset of blocks
2. Create a Block with a different Layout field to accomplish subgrid
3. Add that block to the initial set of blocks of the main Layout field.

Your setup

Kirby Version
4.4.1

PHP version
8.3.8

Your system (please complete the following information)

• Device: HP Omen
• OS: Windows 11
• Browser: Firefox Developer
• Version: latest