Beside and With

Beside preposition - In addition to.

With and beside are semantically related in next to topic. In some cases you can use "With" instead the word "Beside" as an adverb or a preposition, when it comes to topics like alongside.

With preposition - As the result of.

Beside and with are semantically related in position topic. You can use "Beside" instead the word "With" as an adverb or a preposition, if it concerns topics such as accompanying.