Yes. It absolutely is. People fall for the trap of thinking that just because a boss has inherent patterns and weaknesses that it means it isn't difficult because you can learn that pattern and weakness. That's flawed thinking. It's like saying that every single game, aside from really well designed pseudorandom based games, isn't difficult. The difficulty in everything from the old megaman games, the nintendo-hard games, bullet hells, fighting games, every shooter that isn't multiplayer, etc. etc. etc. etc. somehow isn't difficult because you can learn patterns and thus beat bosses. Somehow no one noticed how (/hysterical_sarcastic_screeching) absolutely no game they liked was ever difficult because it could be beaten?
I'd say that a game's difficulty has mostly been about how long it takes or how easily a player could learn said patterns. Do you have to simply repeat the boss a thousand times? Or do you need to take a moment after each loss, analyze the battle and can do it in 5 tries? The 'dark souls' type of game is really good at stepping around that issue by baiting players into straying from a pattern, making the 'time-to-learn' longer and more obfuscated. They also give you several ways to slot yourself into the pattern, which makes it even more difficult (ha) to compare yourself to the videos that many today watch to gauge others and yourself on the same measure.
I'd put elden ring as mildly difficult. It's certainly easier (and maybe more streamlined/optimized) in the level design, which makes it much easier for a person new to these types of games to wrap their head around (and I'd argue that when a player learns any games map is when they start to have an easier time of things; the same reason that turning down the radio when you're lost makes it easier to determine where you are), and its bosses are very much 'smooth' in their fighting and telegraphing, which allows for the player to not put in as much effort to learn the patterns. None of that changes that it will likely take dozens of deaths per boss for most people to beat them.
He's pretty much the perfect example of pulling the ladder up behind you with his policies about disabled people. You could throw in there the eventual instance of the inner circle turning against him, but that hasn't happened quite yet.