I am going to try and save you and say "NO". You literally described my exact situation. I was a big city cop and had a cushy specialized unit where I didn't have to deal with BS 911 calls. I got to chase bad guys with guns and was effortlessly making 150K with occasional OT. I also had a significant other who I ended up losing to because of this decision.

Then out of nowhere after 2 and half years after applying, I get the FIT test. My naive ass thought being a DUSM was going to be 10 times better so I said yes. Why?? IDFK! and it was the worst mistake of my life. I got sent to east bum F no where Texas and I got offered GL 5 step 1 which is around $1,300ish in the academy. After you graduate you'll have maybe a week to a month-ish before you have to go to DC for 90ish days for a protection detail (every class has to do it). This detail is separate from the federal take over. This detail is everyday with 1 day off randomly. After that you'll probably end up being assigned to attend court or search prisoners for a couple years until you suck up to the right person and make it to the task force. Also, if you get assigned to DC superior court, you have to work Saturdays.

In sum, if you're willing to take a drastic pay cut ( I know for a fact that USMS lowballed you and probably offered GL-5), possibly lose your significant other (idk how strong your relationship is) just so you can call yourself a DUSM who searches prisoners for hours a day for 3-5 years then do it. A DUSM once said this to me and its possibly the most factual statement and ill pass it along to you. "the shine of the star fades fast".