You’ll get hired at a regional instantly and they’ll send you to a course to get an ATP. It would just add an extra couple weeks to your training footprint. LTs in my squadron with 750 hours TT are doing it all the time. Your ATC background would be a huge plus for your major/cargo/LLC application after doing a couple years at the regionals, as it would separate you from the vanilla Embry Riddle to CFI to regional FO to regional Capt crowd, who are getting hired in droves right now regardless. I’d do it if I were you. It’s clearly what you want to do with your life or you wouldn’t be asking the question. Don’t let your dreams be dreams.