The time is definitely right for a big budget, R-rated Spawn movie.
The character has experienced something of a resurgence in recent months and movies like Venom shows how much my generation loved the 90s heroes anti-heroes. And Spawn was arguably the biggest anti-hero of the 90s, seriously, the title was the top seller in the country for a very long time back then until the book started meandering into boring muck.
I think part of the problem with the new projects is just how much McFarlane wants to be involved in them (I believe he wanted to direct the last project that fell apart). It’s understandable that he wants full creative control (part of the reason the Harry Potter movies turned out as well as they did was because JK Rowling had final say on all creative choices) but he should cede the film making process to actual film makers.