Blood yup i’ve always felt planes were important; for example my alt had finished amelia before building a lvl3 factory or any bunker.
having 4-5 lines of fighter buffs over 2 artifacts isnt too hard to achieve if you just keep at it. i dont let uncollected fragments reach capacity unless i sleep. my main has 5x6% buffs with rerolls, my alt has the same level of fighter buffs
without rerolls lol. someone in tactics forum has 6 lines of buff for a single unit type, though his thing is cavalry not fighters
as for having enough stuff to upgrade them, i didnt spend any supplies on any artifact i had before my current weapons, living on 1-line 1-upgrade artifacts while holding out for good ones. which is what i am doing now for jewelry. i have 2 artifacts with -11% in first lines that i upgraded once each for total -24, and before that, i had 2 artifacts with +11% all loot in first lines, upgraded once each to total of +24. non-spenders gotta save