WordPress Builders and Starter Kits
A decade ago there were WordPress services were selling WordPress themes - customizing them was cumbersome and hence it was either using the theme as is with minimal UI changes or developing a new theme from scratch.
Since version 5.0 of WordPress in December 2018, it included a block-based editor named Gutenberg which allows users to customize the page's UI block-wise which can be worked upon by non-coders, and as a result, WordPress services started providing 'builder' services where one can customize a theme based on a builder's block HTML+CSS code within the admin instead of touching source files.
Here are a few of such famous 'builders' where which include starter kits (themes) if someone wants a jump start or else building one from scratch without necessarily touching a pre-made theme file.
I haven't used most of these - people I have associated with in the past, who are digital marketing gurus, use these extensively and got some feedback, so my reviews would be non-first-hand. Most of them have a trial, so please see which fits your requirement. If you are a freelancer or an agency then try going for the lifetime plan.
Elementor - most popular for a very long time - $59 a year per site - oldest in the market, famous for its ubiquitous drag-n-drop
WP Bakery - $56 for a single WordPress website
Elegant Themes - $89 a year OR $249 lifetime, both for unlimited sites
Kadence WP - $129 a year OR $699 lifetime, both for unlimited sites
WP Astra - starting at $47 a year OR $227 lifetime for unlimited sites
Brizy - $49 per year for a single WordPress website
For WordPress, I recommend a combination of DigitalOcean and ServerPilot. DigitalOcean is a server service provider and ServerPilot is a 3rd-party cloud control panel for DigitalOcean. The most economical plan on DigitalOcean is $4 a month and a WordPress site on it via ServerPilot is $5.50 per month - it's actually $5 per DigitalOcean server and $0.50 per WordPress site, so it would be $9.50 per month for one WordPress site, $11.50 per month for 5 WordPress sites and $14 / mo for 10 WordPress sites.