It's ridiculous to suggest corporations will treat their customers better if they have competition? That if their customers have somewhere else to go they have more negotiating power?
Adobe and Figma are competitors, right now, regardless of whether they have product lines in direct competition, at this moment.
No they aren't. Having product lines in direct competition is the fundamental definition of being a competing business.
I doubt their executives agree that one another are not a competitive threat. They wouldn't have tried to merge if they weren't playing ball in the same court.