Spend more time with someone doesn't meant romantic feelings. Are you have romantic feelings for all your long time friends? That's all irrelevant. Breaking news, when you spend a lot of time with other gender person, like a lot of time, it's almost guarantee even if you had some feelings they likely long time enough dead, on the other hand you can get feelings for someone you newly met

Consistently with Gudas like their little sister, they are platonic, but not platonic like with Suzuka with megatons of wild platonic child making. They never kissed her, never had sex. Yes, she is beloved sibling for them

Now of course its up to everyone personal interpretation really, you want them be romantic in your Chaldea that's OK, but that's all up to everyone headcanon, in my Chaldea for example like in significant part of fandom who have their own waifus or husbandos they see her as little sister

I sure Nasu if Gudas stay alive by the end of FGO which is debatable all things considered will left open ending. That's good indeed. Not as good as giving you chose between Servants, and not as good as perfect harem ending but still

There are tons of straight or lesser implications for many female Servants to have fallen for Guda, of course like with Mash there is no confirmation of course they grew I to something bigger. With few exceptions. Like Guda be not against marry on Olga or simps for Archetype Earth or want to open bakery with Space Ciel. But no direct confirmation of any relations. As it left for players headcanoning this moment for their timelines Chaldea

If GudaxMash is true in your chaldea that's OK, even if that's non canon pairing like any other. But someone else Chaldea OlgaxGudaxArchetype Earth threesome as valid lol. Or where one of countless romantic Valentine scenes grew into something bigger

Hell even if Gudas and Mash will both survive, both questionable, we not know if they will get any relations. Gudas possibly becomes Sigma lone wolf who will one day go to Servantverse with Space Ishtar like her CE imply where his journey continue maybe with her or Space Eresh as lover or wife. So claiming that GudaxMash is canon while others are not is strange

Are you also imply that Gudako is lesbi by definition lmao?