what do you mean by that "kernel upgrade during Linux update"? And why do you want to do that?
If your goal is to prevent newer kernel's from being booted due to an issue you have encountered with a newer version, you can pin the kernel with the proxmox boot tool. Just execute proxmox-boot-tool kernel pin <kernel-version>. You have to replace <kernel-version> with a kernel version reported by the command proxmox-boot-tool list.