If your content was ok on Patreon, it will be ok on Itch. The reverse is not true. Patreon has some particulars, that they ban.
If you have payments collected by Itch, well, Patreon collects money by the same Paypal as Itch does.
If you have direct payments, then you need permission from Paypal for selling adult things. I would imagine they do not give that permission to every small time indie dev that asks. And even taxes might be a problem there.
There is no subscription, but projects can be bought several times and Itch has the pay what you want pricing model. So people can overpay.
You can make devlogs and blog postings, those are shown to your followers.
You could periodically create a project collecting your latest art works.
You can have access price tiers on a project. Those are made by having multiple individually priced files. You can rotate those files by hand. Like have a project where you put the files for 20, 15, 10, 5, 0 and rotate the files in for 20 and make them cheaper after a week/month.
It also depends, if you release your art for free eventually or what your Patron's benefits were. Some of this can be simulated. There is for example a limited pool of goodies you can sell extra on a page. https://itch.io/docs/creators/exclusive-content#how-you-can-use-rewards/giving-l...
You can also change the price later. So you could put your art collection at higher price for dedicated supporters, and like a month or later you lower the price.
The pricing options are detailed in the faq. The main difference to Patreon is, that Patreon is centered on subscription to a creator and Itch is centered on projects. So for an artist, collecting the art works of a few months till a nice project is formed, is probably the most natural option. But this depends, if the art is supposed to be behind a paywall, or supposed to be accessibly by everyone eventually and Patrons only get the benefit of accessing it earlier as a thank you for the support. But even with paywall, usually you would get access to the previous works at one of the subscriber tiers, for the price of one month. If you distribute it over several projects, one would have to buy all of them. But access to a project lasts, while with a subscription you can only access it, while subscribed.