debian - network(manager/device) problems - wifi - need network excpert :)

hi there.

hardware:
its not a standardPC, it's an industry-PC from owasys.

operating system:
debian 11

my network-setup:
* wpa_supplicant
* network-manager
* (the interfaces file is shown below.. here u can see which wpa.conf file should be used)

i have following problem:
during the booting, the network-manager can't be started anymore.

if i check may environnents with /sbin/ifup -a --read-environment i get following result:

/sbin/ifup -a --read-environment
wpa_supplicant: /sbin/wpa_supplicant daemon failed to start
run-parts: /etc/network/if-pre-up.d/wpasupplicant exited with return code 1
ifup: failed to bring up mlan0

also my networkstation tells me the same:

debian@192.168.43.88:~$ /etc/init.d/networking status -l
networking.service - Raise network interfaces
Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Thu 2023-08-17 13:02:03 UTC; 9min ago
Docs: man:interfaces(5)
Process: 13062 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
Main PID: 13062 (code=exited, status=1/FAILURE)
CPU: 103ms

Aug 17 13:02:03 A12PJX wpa_supplicant[13087]: nl80211: deinit ifname=mlan0 disabled_11b_rates=0
Aug 17 13:02:03 A12PJX ifup[13082]: /etc/network/if-pre-up.d/wpasupplicant: 120: cannot create /dev/stderr: No such device or address
Aug 17 13:02:03 A12PJX ifup[13077]: run-parts: /etc/network/if-pre-up.d/wpasupplicant exited with return code 1
Aug 17 13:02:03 A12PJX ifup[13062]: ifup: failed to bring up mlan0
Aug 17 13:02:03 A12PJX systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Aug 17 13:02:03 A12PJX systemd[1]: networking.service: Failed with result 'exit-code'.
Aug 17 13:02:03 A12PJX systemd[1]: Failed to start Raise network interfaces.
Hint: Some lines were ellipsized, use -l to show in full.

here are all my devices:

nmcli device
mlan0 wifi connected --
uap0 wifi disconnected --
uap1 wifi disconnected --
eth0 ethernet unavailable --
bond0 bond unmanaged --
canfd1 can unmanaged --
canfd2 can unmanaged --
canfd3 can unmanaged --
canfd4 can unmanaged --
lo loopback unmanaged --

as you can see, i cant start my wifi connection if the network-manager...
but after startup the wifi is conntected !

iwconfig

mlan0 IEEE 802.11-DS ESSID:"keke"
Mode:Managed Frequency=2.412 GHz Access Point: 24:2E:02:57:A4:DA
Bit Rate:72 Mb/s Tx-Power=24 dBm
Retry limit:9 RTS thr=2347 B Fragment thr=2346 B
Power Management:off
Link Quality=4/5 Signal level=-51 dBm Noise level=-95 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:29445
Tx excessive retries:2643 Invalid misc:3842 Missed beacon:0

finaly: on the one hand, the systems tells me that he cant find mlan0 because the system can't start networking manager during startup because of mlan0...
on the other hand, mlan0 is is connted to the wifi and it works well (can ping google etc.)

I assume:
i think the problem is, that i changed one line in /etc/interfaces

allow-hotplug mlan0
auto mlan0
iface mlan0 inet manual
wireless-power off
wpa-roam /etc/wpa_supplicant/wpa.conf.handy

iface default inet dhcp

the line i changed is

iface mlan0 inet manual

bevor my change it looked like:
iface mlan0%<mlan01 inet manual

it was a combination from mlan0 and mlan01... i wanted to undo my change, but finally i have the problem that i can't remember the code before exactly...

my question:

the must interesting output is the message from ifup:
ifup: failed to bring up mlan0

he doesnt find mlan0, even mlan0 is connted to wifi...

as u see in my device list,he can find mlan0.. is it possible that this is a link to mlan01 ?
i am sure the deltated part of the code included mlan01 , not uap0 or uap1

how can i find out if there is also a mlan01 and how can i find out if mlan0 is linked to mlan01 ? (e.g. a wlan-stick in a usb hub)

If you have any ideas or any questions, please tell me ..

big thx for your help !!!