I mean, I have to swap glasses (sun to regular) upon entering/exiting buildings too...juggling the cane even (though a cane for walking as I can see well enough out of my left eye to walk around, at least for the time being) and my lenses are so thick I was told transition lenses are not an option for me.
So I understand your struggle.

But, as life has proven to me time and time again, it could always be worse.

Sounds like you need a pair of clip-on shades to attach to your inside glasses.

I know this feeling. And transition lens aren’t an option, because they only react to direct sunlight.

I’m actually working with a couple teams of engineering students to design a pair of glasses that will tint automatically based on lighting, and have manual controls as well. My local university has an accessibility design engineering course, where groups of students build something to solve a client’s accessibility issue. The end design is open source in will be published on their website. For me, it’s adjustable sunglasses.

I’m photophobic. I wear a glasses chain

Not sure how photophobic you are but, since the light is usually from above, maybe get sunglasses with the graded shading, where they are dark on top and then clear at the bottom (kind of a bifocal effect)...I also like to have the kind that are meant to go over glasses to block light that bleeds in from the side and top. I'm albino, though, and very photophobic, so the level of shadong I needed at the top meant the bottom couldn't be totally clear, so I have to take them off indoors. Mine were actually shaded at my eye doctor, and they didn't charge for that service since they were not prescription.

I wouldn't say I'm anti-photo but I get annoyed with how obsessed sighted people are about taking pictures and looking at pictures together when it's supposed to be a social setting. It's just rude to talk about something I can't see right in front of me like that. And however much they explain it just feels like they're taking pity on me or something.

I’ve never been diagnosed but this is how sensitive my eyes are. They make contacts that block uv light. I’m not sure if you can wear contacts or not but it’s something to look into. I’m not sure how it works on all light though. I think they are acuvue oasis. Maybe these aren’t going to help with the adjustment you need though. If they are still doing it they will send you a free pair to try. I haven’t called yet but have been thinking about doing it. I’m not sure if they sell them without a prescription but they should. If people like us with very sensitive eyes suggest that they start selling them without a prescription maybe it will make them think about it. My great aunt used to have transition glasses that adjusted to the dark. If they would make those without a prescription maybe that could help. I know it’s hard having this problem and I hate always having to take sunglasses around. I take walks on a busy street at night and the car headlights blind me but sunglasses make it hard to see the sidewalk. It sucks. Best of luck to find something to help.