What semantic field underlies 即? I can grasp how卩 (“to kneel”) relates to definitions 1-3 below. But how does 皀  + 卩 compound to mean definitions 4-14 that don't relate to food or kneeling and that all differ from each other? Definitions 5 and 7 are the ones that overlap at all!  I screenshot Yellowbridge.

即 - Wiktionary

Glyph origin
Ideogrammic compound (會意): 皀 (“ancient round-mouthed food vessel”) + 卩 (“to kneel”) – to come near to eat; to approach.
Definitions

† to come near to eat
† to approach; to come near; to be near
† to ascend; to go up; to assume office
† prompted by the occasion
† though; although
† if; assuming
† even if; even though
† then
† while
† as soon as
namely; that is; to be the same as; i.e.
† promptly; quickly; immediately; at once
† at present; today
A surname​.
imo, yexxxxxxxxxx and wikxxxxxxx are suitable for beginner only. if you’re interested in etymology, use proper, and better tools; please.

multi-function chinese character database (漢語多功能字庫)

it’s maintained by the chinese university of hong kong

http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=即

read the text in the middle, compare the character in oracle, bronze and seal script.

or, try the 小學堂 , of taiwan

http://xiaoxue.iis.sinica.edu.tw/yanbian?kaiOrder=497

read the character in oracle script, make a mental image :)