iOS Safari does have a "Page zoom" setting that can be set per-site or as default in its settings, which is really mainly increasing the font size. It's probably not exactly as you like in Chrome.
I have tried this setting multiple times, but it doesn't do what I expect it to. I just tried it again on my wife's iPhone 12. I set the default page zoom to 200% and opened one of my regular sites (tweakers.net (Dutch)). When opening an article the content is zoomed in. When I pinch-zoom out the text size is small again.
On Chrome (Android) whenever I set the font size to 200% the behavior is more or less the same as on desktop. So the content is zoomed in and text sizes are huge. On iOS Safari Reader Mode works the way I expect to, but I find this a bit of a faff to use.
On Chrome (Android) whenever I set the font size to 200% the behavior is more or less the same as on desktop. So the content is zoomed in and text sizes are huge. On iOS Safari Reader Mode works the way I expect to, but I find this a bit of a faff to use.