Learn English – n expression to say someone will replace me at a meeting

This is perfectly grammatical. You can use a present-tense verb with "if" to talk about the possibility of a future event - check out my answer on Future tense in conditional clauses for more details.

For the second clause, your intuition is correct; "would" and "will" mean the same in this context, but "would" is a little less direct.

You may use: where there's a will there's a way:

• used to mean that if you are determined enough, you can find a way to achieve what you want, even if it is very difficult

(Cambridge Dictionary)

Also:

will power:

• The strength of will to carry out one's decisions, wishes, or plans.

• You may say that it is only a question of will power to achieve to do something.

(AHD)