I have not noticed any boot time change between USB boot (multiboot) and SDcard only boot.
Unfortunately, I don't know what boot scripts you actually use, since you said you didn't use the toothpick method again. The boot order may also be different, so the information is unfortunately not relevant.
By the way, it might be device specific, but for me it takes 10 seconds for the USB ports to be scanned, which is a lot for me.
Normally, once boot, I always keep it on or on standby mode & use remote to wake-up.
In this build, power-off have only 3 option (power off, custom shutdown & restart), don't have 4th option for suspend (sleep). I had to override in setting - power saving - Force suspend instead of poweroff .
For many devices, standby mode is not the default or is not available at all. This is also a uboot-specific property defined by the manufacturer. (By the way, this "Force suspend instead of poweroff" is only available in my builds, because it's my own solution.)
And, if someone boots from an internal NAND/eMMC, they always have to wait to scan the USB unnecessarily. And, since many people can't even use the suspend option, every start will take forever. This is not good, so we need an intermediate solution that is acceptable to everyone, and I am currently working on this.
The original 3-script solution is unnecessarily overcomplicated. I'm currently testing the single-script solution and I introduced a small modification, so the USB boot is inactive by default, but it can be simply activated by an fw_setenv enableusbboot 1 command.
I installed docket but how to install portainer? It's not in add-on. Needs to use CLI?
It is recommended to use the CLI, but there are many places describing how to use it, so I don't want to write complex documentation for this.
mkdir /storage/.config/dockers
docker run \
--name=portainer \
--restart unless-stopped \
-v /var/run/docker.sock:/var/run/docker.sock \
-v /storage/.config/dockers/portainer/data:/data \
-p 9000:9000 \
-d portainer/portainer-ce
