Learn English – “Most” is used as an adjective and an adverb

There are a couple verbs in English that are allowed to take adjectives in some circumstances. These are called copulae: words that link a subject to the predicate. (Though in a linguistic context it often means some word corresponding to English "be".)

These include:

• "be"
• a couple verbs relating to what we sense (look, feel, smell, taste, sound)
• "seem" words (seem, appear, act,)
• "become" words (become, get, come, grow)
• "remain" words (remain, keep, stay)
• "turn out" words ("prove", "end up", but not "turn out")

Beware that copulae are lots of times used non-copulatively, and often cannot take adjectives elsewhere.

I slowly turned the wheel.

but

I got angry.

and

Carefully prove this theorem.

but

Lawrence's jargon proved incomprehensible to outsiders.

and

The puppet came alive!

but

He came into the room.

https://en.wikipedia.org/wiki/List_of_English_copulae

When "more" is used before adjective or adverb as "inconvenient" in your example, it is an adverb whose primary function is to modify the following word.

However, when it is used before a noun (or sometimes after a noun), it is used as a determiner or adjective. For example:

I need more money.
More context is required.

I need something more (to eat).

In the above examples, it means:

greater in amount, number, or size, extra or additional