Ah, yes, the "rocks fall, everybody dies" kind of an ending, except positive.
Not gonna like, it kinda marred my opinion of the series as a whole. The first part was easily a 10/10 in my book, but ever since the Demon King arch it fell to maybe 7/10 or so. Overall, 8/10, would read again.
10/10 manga, 8/10 ending, will re-read one day for sure.
I don't mind the open ending, to be honest. Especially since, should this manga make it big some day as an anime or something, it leaves open space for a potential sequel.
Or, alternatively, go to a site that actually loads the manga and doesn't trigger the antivirus after showing fake-notification ads.
There's a good reason people use aggregators.