At least for romance languages, there is a rhyme and reason for the gender each noun gets, so neologisms and borrowed words tend to follow the same logic.

For word morphology, as an example, in Portuguese nouns ending in a are almost always female, so new words that end with a are very likely to be female.

There are semantic rules too, for example brands and companies are typically (I want to say always but there's probably edge cases) female, so even though Netflix and Amazon didn't exist before they're still female.

In slav languages, you just go with how the neologism sounds. "Computer" ends in hard r, so it's masculine, for example.

Every once in a while there's going to be shit like with "coffee" though. It sounds neutral-gendered and is officially neutral-gendered, but there's been a big period when people believed it should be masculine because of the source language or some shit. Still a lot of people arguing about it.

Depends on which word you use. At least in German.