Cryptomator on Apple MacBook Air M1 with nextcloud very slow

I use crytomator with data in my nextcloud (hosted on my Synology NAS). If I use my android app everything works fine with normal speed for opening files. But if I use my Macbook everything is very slow. My files are round about 300MB and 100 Images. To generate the preview pictures, it takes more than half an hour.
Also, I’m not able to close cryptomator normally. It can’t close the vault and my whole system gets very slow. Sometimes I’m unable to do anything else and have to reboot the system.
I’ve tested it with and without macfuse installation. I think the problem is the WebDAV connection, but is there a possibility to increase the speed or use an other connection for a nextcloud hosted vault?

OK, I found a way to get more speed with cryptomator and nextcloud: if I use cyberduck for the WebDAV connection, I can work with it. But there’s the disadvantage that there are no preview pictures available.