The context is technical in the IT field. Taking for example the
httpsprotocol would you say:
The https protocol is candidate to become in the main standard
The https protocol is candidated to become the main standard.
To me it seems
candidateis more suitable for people rather than for things.
tothe right preposition?
Candidate is normally a noun, not an adjective, or past participle.
Here’s how Merriam Webster defines it
1 a : one that aspires to or is nominated or qualified for an office, membership, or award
//a candidate for governor
//a candidate for “Manager of the Year”
//the best candidate for the job
b : one likely or suited to undergo or be chosen for something specified
//a candidate for surgery
The second definition fits this context: “The https protocol is a candidate to become the main standard” or “The https protocol is a candidate for the main standard.”