Ah ! Been there, done that. 7 years ago, at 33 I was at your shoes. I left my narrow body command ( did not 1000hrs pic) for a widebody middle east right seat job. Made twice or at times thrice the money than that narrow body job back home. Travelled the world, fulfilled my dreams. It was 5 awesome years until the coivd hit us hard. I do not regret my decision, because the company I left, treated me/us like sh)t. I did want to give them back. And I am glad I could do it. Not everyone eats s&it to get command, only some do. Looking back, Yes logging that one or two thousand pic hrs would have been nice but hell ya, even capts with 1000s of widebody jet PIC are right now sitting at home with no jobs. And I wouldn't bought German sports car that ran on cheap fuel, and wouldn't have did all that international travel when my kids didn't go to school and when my wife wasn't working. I cant do it now, as they all are busy. So no regrets. Everything in life happens for a reason.
Now looking at your case, at 40 say if you join Qatar, and they fire you after 5 years as FO, you'll be ineligible for most of the FO jobs. Like all the wisemen's advice here, its always better to get left seat and shift from left seat at career perspective. 3 years from now you will be eligible for Qatar DEC job, or EK DEC (as they are getting 787s too) if middle east is the only place you want. There is going to be heavy shortage of captains in this region in the coming years.
Or If you are adamant on going now, log your 1000PIC, pay your bond and join Emirates, that if you clear the assessment. Emirates and Dubai are way better than QR with a little compromise.
Else take that huge risk of joining QR, many are happy in Qatar too. You can always leave during probation or in 3 years if you don't like. But leave your current LOCO on good terms.
Adios !