Currently you look up the timezone, maybe do some maths (but let’s be real, you just search and get given the time) and then you immediately have a good sense of what the time is there, oh cool it’s 7AM.

If we all had the same timezone: you look it up, and then you HAVE to do maths. Why? Oh their midnight is 8, and it’s 15 now, so 7 hours after midnight.

it's the exact same amount of math in either scenario, arguably even less. Let's say you're setting up the time for a meeting with someone across the globe over zoom or something for instance. How does it go? Well you ask them what they're schedule is like, and you already know what your schedule is like. And both of them use the same timezone instance, because there is only one. So you do no math other than shifting it directly forward and back, the associated amount of time. Perfectly simple. You could also google it ig, but that's going to the exact same, minus the abstraction that you would otherwise have to do with timezones.

If we all had the same timezone: you look it up, and then you HAVE to do maths. Why? Oh their midnight is 8, and it’s 15 now, so 7 hours after midnight.

This is called a timezone. "Midnight" is the same time everywhere, unless you're talking about the literal mid night. In which case, yeah that changes, but i'd question why you would need to know that. It's not like you don't already know that. Google has already told you. Assuming we're talking about the date/time midnight, that's the same time, in every place of the world. Doesn't matter, midnight here (assuming the 00:00 standard is continued for some reason) is midnight in fucking norway or, sweden, or bulgaria, or your moms house. Doesn't matter.

No matter what time you pick to anchor what time of day that place is, the problem persists. And now you just have replaced the problem of looking up timezones, with looking up when the sun is at some point, and then needing to convert that to get a sense of what time it is there according to the sun.

See this is where you go wrong, i'm saying timezones SHOULDN'T exist, and then you immediately propose a system that is also just a timezone, they shouldn't exist PERIOD. There is not link between the solar cycle, and date/time, other than the fact that they exist in a parallel fashion. There is no anchor to what "midnight" is, midnight is just the middle of the night, that might be 2 am, that might be 5 pm, that might be 14:00 who knows. Who cares, it doesn't matter.

And let's assume that timezones are nice, because you get up for work at 6am, and they get up for work at 6am, and you both stop at the same time. Sure timezones are nice in that one specific instance because it's a direct translation, you know what else is a direct translation though? Not having timezones. You could just as easily convert "timezones" into "solar cycle maps" Literally the same thing, they explain the same exact thing, they use the same exact amount of effort.

It's literally only LESS confusing now.

Your mind immediately has gone to oh it’s 7AM, but NO, in this new reality, it’s 15:00 everywhere and where you live midnight is 14:00, so that means where you live it would be like your 21:00.

There is no 21:00 your time. it's 14:00 your time. 14:00 is your midnight in that instance, because that's the time where the middle of the night occurs for you. 15:00 for you is one hour after you midnight, and 15:00. It's not magically 22:00 now, or 1:00 now. That's not how that works.

I suppose you could be arguing that you are so entrenched into this particular method of counting, that the numbers the funny paper disc tells you is actually how you control your sleep cycle, but i would much rather argue, uh no. The sun does. Why? Science.

quick edit:

This would be shit, when you get to a new country when travelling you have to relearn what the numbers “feel” like.

Also, news flash, we already have this issue, it's literally called jet lag. This is a normal occurrence. And also, literally anybody who lives in somewhere that DST exist, does this TWICE A YEAR.