I really created the Joplin folder.
Joplin Windows and Manjaro linux sync are OK with the same setup of the nextcloud.
The Joplin Android does not has “Ignore the error of the TLS” just like desktop edition.
It’s unlikely Android will have this feature, however if I’m not mistaken you can manually add the certificate on your device. Or you can use something like Let’s Encrypt which would just work.
I used Let’s Encypt to add SSL to all my sites including Nextcloud. It works like a charm.
However, that being said, I did not have any sync problems with the Android app before even when using plain http. I think it must be some other problem in this case.
I changed my server to a new nextcloud application vps on vultr, it provide full nextcloud environment after deployed with ip connection.
It is correct after sync with Joplin-desktop, selected TLS.
But android sync is wrong after testing two phones.