Is it? it’s certainly no worse than EasyJet, and unlike the larger transatlantic carriers (ba/united/delta are the ones I’m most experienced with) the websites are navigable, performant, and actually functional.

Meanwhile booking.com has a recurring pattern of diverting you via search results to show you extra sponsored results. My experience is that Ryanair is far easier to navigate and book than Booking.com

I recently ordered ticket from Ryanair, if you simply look for the "next" button nothing is a mess. The only somewhat messy thing is the content of what you buy, for example a family package has only one large suitcase which is unusual, and that Ryanair are super strict at the airport- I saw someone taking out socks to remove extra 300 grams from their suitcase.