This will only work if there is a solaar executable at that path, which there would not be by default after installing the package.
So OP seems to require it be started with sudo or as root.
I have no idea if this makes sense or if there another option, as I do not use solaar.
And of course we generally do not want to start graphical programs with elevated privileges, and solaar seems to be that.
But if we think thats what we need to do then a service like the following probably makes sense;
File:
/etc/systemd/system/root-solaar.service
Contents:
[Unit]
Description=Automatically start root solaar
After=default.target
[Service]
user=root
Type=simple
ExecStart=/usr/bin/bash -c '/usr/bin/solaar --restart-on-wake-up --window hide'
[Install]
WantedBy=default.target
Enable service:
systemctl enable root-solaar.service --now