Edit upload file permissions (Umask)

I need to modify the permissions of uploaded files
How should I use the script to start the service and modify the Umask at the same time?

Some past experience

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Ubuntu server has a user ‘teamspeak’ dedicated to the teamspeak thread
The create command is ‘ useradd -s /usr/sbin/nologin -r -M -d /opt/teamspeak teamspeak ‘
And i will use command ’ cat /proc/$(pgrep ts3)/status | grep Umask ’ to check “Umask”
And i will use command ‘ls -l /opt/teamspeak/files/virtualserver_1/channel_1/demo.txt’ to check “permissions”

1、 sudo -u teamspeak ./ts3server
Umask: 0002
-rw-rw-r–
2、 sudo -u teamspeak ./ts3server_startscript.sh start
Umask: 0000
-rw-rw-r–

3、Systemd
Umask: 0000
-rw-rw-rw-

/etc/systemd/system/teamspeak.service
[Unit]
Description=Team Speak 3 Server
After=network.target
[Service]
WorkingDirectory=/opt/teamspeak/
User=teamspeak
Group=teamspeak
Type=forking
PermissionsStartOnly=true
UMask=0022
ExecStartPre=/usr/bin/mount -t tmpfs tmpfs /dev/shm
ExecStart=/opt/teamspeak/ts3server_startscript.sh start inifile=ts3server.ini
ExecStop=/opt/teamspeak/ts3server_startscript.sh stop
PIDFile=/opt/teamspeak/ts3server.pid
RestartSec=15
Restart=always
[Install]
WantedBy=multi-user.target