Kodo

Slug-Free Permalinks lets you switch selected post types and taxonomies to simple ID based permalink formats.
You can choose between:
<ul>
<li><code>/post/123/</code></li>
<li><code>/post-123/</code></li>
</ul>
The plugin only affects the post types and taxonomies you enable in the settings screen.
Features:
<ul>
<li>Select individual public post types</li>
<li>Select individual public taxonomies</li>
<li>Choose slash or hyphen based ID permalink format</li>
<li>Optionally redirect legacy slug URLs to the current ID based permalink when WordPress can resolve the request</li>
<li>Preserve prefixed permalink bases such as <code>/en/</code> when another plugin adds them</li>
<li>Flush rewrite rules automatically when settings change</li>
</ul>
This plugin is focused on permalink structure only. It does not add content features or front-end UI.
Plugin page (English): https://happas.jp/en/slug-free-permalinks/ 
Plugin page (Japanese): https://happas.jp/slug-free-permalinks/
Development repository: https://github.com/1008k/slug-free-permalinks
This plugin is best suited to new sites, sites still defining their permalink policy, or structured-content use cases where slug management is unnecessary.
If your site already has a large number of published posts and established slug based URLs, review the impact carefully before enabling it. Check existing inbound links, search traffic, social shares, and editorial workflow assumptions.
Known limitations:
<ul>
<li>If a post type slug and taxonomy slug are identical, their ID based rewrite patterns can conflict.</li>
</ul>

Slug-Free Permalinks – Simple ID-Based URLs

Use ID based permalinks for selected post types and taxonomies without managing slugs.

Dimitris Mavroudis

AutoConvert Greeklish Permalinks converts greek characters to latin in all permalinks. The plugin makes sure that every new permalink is in greeklish and offers the option to convert all the old links with greek characters to latin.
<h3>Features</h3>
<ul>
<li>Convert automaticly the permalink of every new post and term.</li>
<li>Convert all your older posts and terms with a click of a button.</li>
<li>Choose how dipthongs are converted. </li>
<li>Developed to be friendly to developers with WP-CLI support and filter to modify the converion.</li>
</ul>

AutoConvert Greeklish Permalinks

Thank you for sharing this plugin. It works very nice both using the classic WordPress Dashboard as well with the Rest API.

Very good plugin.

I was ready to "reinvent the wheel" but just then i found this plugin

Does exactly what it says

Convert Greek characters to Latin on all your site's permalinks instantly.

Slug-Free Permalinks – Simple ID-Based URLs vs AutoConvert Greeklish Permalinks