I mean i think there are pretty clear cut off points we can accept like the koike movies being there own canon which do connect to mamo as you mentioned, the manga is also its own thing, most anime series are also seemingly not connected, cagliostro also seems unrelated to the rest of the franchise since its implied to be an older lupin's last adventure, twcfm is probably a prequel to part 1.
The koike movies lead directly to Mystery of Mamo, which is directly seen and referenced in Part 5
The manga is seperate however that's due to a bunch of factors including a large chunk of it just being remade into TMS format
Most anime series is just implied to be connected with no distinct cut off points, with countless movies, TV Specials, manga, TV Parts, hell even pachinko machines having at least some amount of evidence where there are some direct reference to a thing or two in that section.
Cagliostro is also directly referenced and seen in Part 5, alongside being seen in other pieces of media like Green vs Red in other manners.
TWCFM is a prequel to part 1 and is likely also connected to the Koike films
The franchise treats everything as applicable, the only cut off points that exist are fan made and aren't used for canon reasons. It's widely accepted that the franchise doesn't follow any typical canon, and if we followed that line of logic to a T and separate everything then we'd have
500 different Lupins running around. The profiles act as a composite of the characters since that's how the companies/copyright holders treat them, which acts as the most straightforward way of treating the cast without just copying and pasting profiles over and over again since most 'versions' of the cast have no real differences with each other.
Hell, even with just Koike films things don't change much since we have the Mamo laser feat and Lupin surviving the black hole at the end of Immortal Bloodline. It's basically just trying to separate things
only to keep them separate because someone else directed the films. (Which would also create 500 different Lupins since the franchise has been made by so many different people)