You may try understanding the word "that" in this way, with the assumption of an optional element dropped:

I also did not love (the fact) that for most purposes, the AirTag requires buying a separate accessory, ...

Now it's an appositive subordinate clause, where "the fact" and the whole subordinate clause beginning with "that" refer to the same thing.

You may try understanding the word "that" in this way, with the assumption of an optional element dropped:

I also did not love (the fact) that for most purposes, the AirTag requires buying a separate accessory, ...

Now it's an appositive subordinate clause, where "the fact" and the whole subordinate clause beginning with "that" refer to the same thing.

In fact, there are many more possible replacement words that fit right there, for example:

• I like (it) that ...
• I like (the assumption) that ...
• I like (the implication) that ...

As long as the word in the parentheses matches that of the subordinate clause, you're good to go.