Mein Deutsch waere viel besser gewesen...

This forum in particular, but also our society in general is tremendously influenced by Grace Hopper's "compiler" (we would not call the thing Grace came up with a "compiler" today but we'd recognise her ideas). Grace appears to be the first person who noticed that the machine could be told to do the boring part where you turn your program into machine code to run on that machine. Grace's idea is meta-applicable, it applies not only to many other things but also to itself, things get out of hand very fast and that's how less than a century later we're here.

Grace was in the US Navy in World War II. Even in our real history where Donald Trump was not President, Grace did not meet their strict requirements for women and so she was only able to get in via a special exemption. Can you imagine in the "Make sure our Warriors look good on TV" world of Pete Hegseth that they'd ever accept Grace? No, the Navy is for big strong men.

The UK would most likely be speaking German now. Possibly even the US.

The USSR would have taken over all of Europe, not just Eastern. What would have happened to the former British and French empires? Presumably they'd have been turned communist, but would their struggles for independence have gone the same way?

The Manhattan project would have been announced before it went anywhere, undermined during development and produced no real result. Japan would not have been nuked, but also would not have been invaded and the Pacific theatre would have in general developed in a completely different way. Without the American nuclear arsenal, the world may have skipped the cold war and nukes, or perhaps other states would have made them and used them in a heavy mutual bombardment without restraint.

Eventually in Europe, glasnost and perestroika would still have happened, and the USSR would still have fallen; but the geopolitical and economic importance of the USA would be little different to that of Brazil.