Your posts have been moved to a dedicated Support topic.
The same warning as what?
Please become accustomed to using the “Reply” (available under each post) when responding to a particular comment; this helps to avoid confusion.
Note that if you were responding to my post immediately preceding yours, then that warning is likely not the same at all, given that it was a suggestion to change the language (which may or may not have been adopted).
Note that warnings are typically non-critical conditions. To address a few of the warnings from your posted command output;
As this may suggest, os-prober is either not enabled or not installed. To allow os-prober to detect other bootloaders (other operating systems) in a multi-boot scenario the following line should be uncommented in /etc/default/grub:
GRUB_DISABLE_OS_PROBER=false
Although this may seem counter-intuitive at first glance, uncommenting this line will enable os-prober; it is disabled by default.
This isn’t a warning, it’s purely informational.
Some tooling doesn’t (yet) seem to account for relatively new NVMe devices, and faithfully report them as an unknown device type even though they function as expected.
This also seems rather easy to understand (to me) and the message to check your UEFI boot priorities (boot order) is equally obvious; and indeed is what you have done.
I’ll note (purely from observation) that the need to reset the boot order after using the install-grub script does arise occasionally with some hardware combinations. Provided there are no other contributing factors to apparent boot failure, booting directly to BIOS and choosing the preferred default loader will rectify that.