For example, via the Termux app or "HTTP Shortcuts" app from F-Droid or Github.
Sometimes corporate apps use resources from their public websites, not a dedicated "endpoint" set up for the app. For example, a weather app that uses pages under a folder called "widgets" from its website, or a grocery app that sources product images from an images folder its website's www subdomain. In testing I have accessed such resources outside the app, outside the mobile OS, from another computer, using any software.
But Termux and HTTP shortcuts are apps, and subject to all the corporate mobile OS restrictions.
There is no sysctl, nftables, iptables, tcpdump, etc. on the "phone".
The kernel is generally not under the control of the phone's owner.
As such, _for me_ the corporate mobile OS even coupled with impressive phone hardware, is inferior to a computer that it's owner, who is not working for a so-called "tech" company selling ad services, can control, by compiling and installing their OS of choice. That includes the kernel.
Using Termux, I could submit this reply to HN from a phone using the 59-line shell script I normally use on a computer. It's possible. But I prefer the computer with the kernel I compiled myself.
If I'm going to use a website instead of an app, I would prefer to do it on that computer, not a "phone".