What would the word PRODESCENDING mean if it were an English word?

It would mean whatever the person who invented that word wanted it to mean. Possibly you are looking for the opposite concept to "condescending". The answers by Kaysyllables and Wingnuts go off in completely different directions. All of those ideas, theirs and mine could be valid.

When new words are invented from elements of other words, they seldom have logical meanings compared with the parts used.

Not a common word.

https://everything2.com/title/Prodescending%253A+O...

In favor of taking the down elevator or escalator.

It could mean "in favor of descending" or "causing (something) to descend."

Well, condescending means looking down on someone because you think you're better than them; the "con-" is the against part and the "-descending" should be the below part, so I would assume prodescending would mean looking up to someone because you think you're better than them.

professional abseiling

professional downhill running

professional parachuting

professional fast rope descent