You're very welcome to run such temporary non-intrusive ads.
I believe a fair amount of people come here because they can't afford to pay (or don't want to) for mangas (and other forms of comics hosted on MD). Donating in crypto already limits who can/is able to donate. Affiliates are hard to come by (though running such ads may help to find some ?).
Running ads is likely the only realistic solution by now. I firmly believe MD team wants to avoid them as much as we do. Hence, I also believe you will manage them as good as you can.
I hope it works out well !
@f8xct Patreon is not possible, this is not a business and is definitely a greyish-illegal area. Mind yourself why Paypal is not possible anymore. Patreons are not donations, they are affiliated to a business/person.