It's likely your favorite websites are showing on ads. This means that websites rely on these ads to fund their operations. Without advertising there is no laughter, no news and no instructions. For this reason, it is helpful to disable content blocking (often called whitelisting) for sites that you support. In the past this was not possible directly in Safari, but the in-app whitelisting became reality with iOS 13.
Everything is related to iOS 13 Safari's new Site View menu. The menu offers desktop-class options (not to be confused with the Desktop class browser that iPadOS 13 introduces), so you can optimize your mobile browsing experience. With the new content blocking whitelist options, you no longer have to mess around with the content blocker app itself. However, the option to disable ad blocking is only displayed if your iPhone has a content blocker installed.
Disabling Content Blockers Simultaneously
In the Settings app, tap the "Safari" menu item and you can see "Content Blocker" at General above. Tap the icon, then turn on one or all installed Content Blocker apps.
Then return to the "Safari" menu and click on "Content Blocker" under the Site Settings section (confusing, we know) to change the behavior for all blockers. This section will not even be displayed if your content blockers are disabled in the first section.
Here you can disable all Content Blockers on your iPhone for all websites at the same time by clearing the checkbox next to "All Sites". If you have more than one content blocker enabled, the option disables all content blockers for all sites. Previously, you would have to go to the other menu and disable them one after the other.
If you are using Content Blocker in iOS 13, you probably want the setting to be turned on. This allows you to directly use the Whitelisting feature in Safari.