Anecdotally:
IMO: Easier to notice, an easier to access echo chamber to recruit, and an increasing lack of critical thinking with more gullible people as the instant gratification of "Karen research" is greater than the long term gratification of reading proper papers and finding out your thought on something just may be wrong.
Many of them are far more adept at social media now, with the Gen Z crowd coming up and many of them having run small youtube channels, or basically born out of Instagram coming up and considering FB an ancient lost society now. Some are learning very early the techniques of manipulation and poor debate skills that make them feel righteous, despite never being able to make a proper argument. I have relatives like this. Very adept at social media and very loud on it when they are quite wrong but want to feel they are right. I'm not sure if they are increased in numbers, but they have learned to be so loud it certainly feels like it. I can't think of a way to describe them except incredibly dull or boring people at this point.
There were deniers for the cholera epidemics and the swine flu, and the first SARS outbreak, that lead in fuel was dangerous... Those that would pretend wearing seatbelts did more harm than good as you could choke to death in an accident or get stuck in the vehicle after it's rolled several times and that NIN isn't the best band in the world... It's just the same crazy repeated again and again over time as they ignore established science. (Granted... cholera and swine flu... science wasn't all that great... but it has gotten light years better and more reliable).
One person who used to be quite close to me is now batshit crazy and convinces others of her age to join in on the madness from time to time with Karen style "research" because the older generations just can't be listened to and trusted since we all just want to hold her back. She is quite a bit louder than those who get exasperated with her constant barrage of "if you don't believe me do your own research" to which "Um... I don't have to, this paper linked on Nature (or wherever) shows exactly why you're wrong and has all the proper references and doesn't come from FreedomForceWebsiteForYourRights dot US slash A" is just proof that we've fallen for the conspiracy and then enters Ad Hominem as they are cornered and have no out to support their position. So it's just about being louder than a reasoned approach until the reasoned person just has to walk away and let them slander you behind your back. So it's no different than 1910... only it's far more visible and easier to get gratification from instant likes rather than waiting a week for the fan letters to roll in.