By this, this config will no longer working:

<?php

use Rector\Config\RectorConfig;
use Rector\TypeDeclaration\Rector\Property\TypedPropertyFromAssignsRector;

return RectorConfig::configure()
    // A. whole set
    ->withPreparedSets(typeDeclarations: true)
    // B. or few rules
    ->withRules([
        TypedPropertyFromAssignsRector::class
    ]);

for default demo page config https://getrector.com/demo

However, when withConfiguredRule() called, it MUST keep working, as override with configurable eg:

<?php

use Rector\Config\RectorConfig;
use Rector\TypeDeclaration\Rector\Property\TypedPropertyFromAssignsRector;

return RectorConfig::configure()
    // A. whole set
    ->withPreparedSets(typeDeclarations: true)
    // B. OVERRIDE RULE
    ->withConfiguredRule(TypedPropertyFromAssignsRector::class, [
        'inline_public' => true,
    ]);

ref https://getrector.com/demo/c74dab61-ff51-47fe-9391-f14bc34fc84a

this also needs test for configurable rule registered multiple times to keep working, eg: multiple config included with configurable rules.

The first example is mutually exclusive. Either use A, or B. Not together.

For second use case, I think the configured rules are now skipped, as withRules() accepts only non-configured ones, right?

No..., withRules() accept configurable rule with default config, so when collect rules, instanceof ConfigurableRectorInterface should be skipped

I've just tagged a new Rector release https://github.com/rectorphp/rector-src/releases/tag/2.0.10,
so we can test this in the wild separately 👍

Let's ship it :)