First of all, "something entirely else" is not a valid construction. "Limited to" is followed by what's possible, what's permissible, or what's present despite of the limitation. It can be either one noun or gerund or a group of them. "Limited by" is followed by the agent(s) or factor(s) that is/are causing or defining the limitation.

A preposition is followed by a noun (or something that behaves like one) called the "object" of the preposition. Prepositions do not change the words that follow. "Limited" changes in no way whatsoever in either of your sentences. In each case, "limited" is an adjective. The phrases "to something else" and "by something else" are adverbial clauses that modify the adjective "limited". "To" *targets* the object of the preposition. For example: "He went to the store." (targets the store) "I gave the book to him." (targets him) "Mommy says you are limited to three cookies." (targets the cookies as the thing that is limited) "By" indicates *relationship* to the object of the preposition. That relation can be proximity or something more abstract: "That play is by William Shakespeare" (the relationship is authorship) "The dog is by the fire hydrant" (the relationship is proximity) "The student is limited by his laziness" (the relationship is the manner of limitation)

For your first question, I don't think the prepositions "to" and "by" change the grammatical function of "limited" in any way. "limited" is technically an adjective in both sentences. I think "by" might make it feel more like a verb than "to" does because it suggests "action" more strongly, but that is just an impression we get. It doesn't make the grammatical role of "limited" any different. There is a clear semantic difference though. "limited to something else" means it is no greater than (i.e. is confined to) what is referred to as "something else", whereas "limited by something else" means another thing is limiting the war (i.e. keeping it from escalating).

it's not "a preposition affect", it's vice versa, the preposition is _required_ after certain words to give the certain meaning, for example "look at", "look for", "go against", etc limit is a verb limited 1 a past of limit 2 a verbal adjective or passive the usage of the preposition depends on the sentence, that is on the other words you use who told you [ "to" is the maximum thing I can have, and "by" is the constraint, the thing that surrounds me] was a real idiot who didn't mention "by" is a part of passive = the book was written _by_ me Your sentences are word by word translation -- isn't clear what you want to say using "or is it limited to something else entirely". Change it completely.