I recently went thru' some struggles with Easy OS on a 'difficult' to access sata ssd that didn't work out. I successfully installed it on the 2nd partition after Linux Mint using a USB Ventoy menu + F6 grub cfg to boot it, but when it allegedly saved, the only thing saved was the files dir. I have a separate thread in an Easy Scarp 663 topic so I won't talk anymore about that in here, except how it related to my question here.
The ssd is partitioned, so I want to be careful about how I put something in its 2nd part, because the boot flag is on the 1st part, and I don't want to change that because of the 'difficult to access' condition, which means that I have to boot the ssd LM via a Plop boot manager, his 'newest' is called PBM6 which I have on an optical. When I do that, the LM boots 'directly' from PBM6 without going thru' a grub menu. I don't understand that; but there are a lot of things recently I don't understand properly.
Here's where I'm going with my Bookworm question. There is an app call FrugalPup (v44). One of its items is FrugalPup icon; my problem is the control of unwanted boot manager effects. Or, maybe my problem is that I should just stick w/ the USB Bookworm + the ssd .sfs. I need to have 'total control' of how the booting is handled, considering that I don't even get to see the boot manager on the part with the boot flag and I don't want to change anything about the boot flag or even its unseen manager, because the last time I did that I lost the ability to boot LM or even fix/repair its (unseen) grub.