Seafile nginx proxy chain

OK suppose the seafile,local with nginx as proxy to localhost is on duty and doing fine.

The next step would be to give it an external access via webservers. Let us call them
web,local - the one who helds the letsencrypt cert and enables connections to /seafile /git a.s.o.
web,public has a virtual doman mydomain;com and proxies to web.local.

In my childish opinion the lean way is

servername mydomain;com
whatever_directive / http;//web,local

servername mydomain;com
whatever_directive_ssl_rewrite http < https
whatever_directive /seafile http;//seafile,local

As every bloody direcories or subservers must be handled by nginx at seafile.,local

Mangling with this problem for months.
Did someone solve this problem?

Tks - willi

see: the link restriction is rude and in this way a big fault.