Thanks for your answer!
I had time again to play around a bit with unbound & pi-hole, so the pihole container was not set to "Priviledge" i think the "Maximum number of concurrent DNS queries reached (max: 150) error" was because i restarted the pihole container and it always forgets the DNS Settings i put in and changes to "listen to all devices", even though i put in "Allow only local devices" and another DNS Server it should use, when it starts again.
So i tested unbound and i figured out that it is not using my pihole.conf file in the unbound.conf.d dir! Dont know why it is doing this... So i tested unbound with the unbound.conf that is in the unbound main dir and it is working fine and answering in the pihole query log with "sent to unbound.br0#5335" like i put it in the unbound.conf file. How can i say to unbound to use my pihole.conf file or how do i fix this?
Another thing i noticed is that it is not using DNS over TLS with the unbound.conf, like with the pihole.conf file when it was recognised.
Also i get the following errors in the unbound log:
[1644065587] libunbound[21:0] error: udp connect failed: Cannot assign requested address for 2001:500:200::b port 53
[1644065587] libunbound[21:0] error: udp connect failed: Cannot assign requested address for 2001:500:200::b port 53
[1644065587] libunbound[21:0] error: udp connect failed: Cannot assign requested address for 2001:500:2d::d port 53
[1644065587] unbound[1:0] warning: setrlimit: Operation not permitted
[1644065587] unbound[1:0] warning: cannot increase max open fds from 40960 to 189120
[1644065587] unbound[1:0] warning: continuing with less udp ports: 1750
[1644065587] unbound[1:0] warning: increase ulimit or decrease threads, ports in config to remove this warning
[1644065587] unbound[1:0] error: Could not open logfile /dev/null: Permission denied