Why go through the trouble of accusing them of implanting a backdoor, if all they wanted is to review other countries' offers, which they're doing now anyway (Russia, China)? Are you saying that now they will go back, and say "ok, since you removed the backdoor, we're going to accept your 30 percent discounted offer."? That seems highly unlikely.
If anything Russia and China will charge them more than the French now, to "guarantee" there's no backdoor, and since they are in a better negotiation position now than they would've been if UAE reviewed their offers pre-accusing France/US of backdooring the other offer.
I like your entirely-appropriate scare quotes there. I can't see any reason to believe that Chinese or Russian hardware (or French for that matter) would be any less likely to be backdoored. I wouldn't trust any of it further than I could audit it myself--which makes it a tricky situation for second- or third-party users, since auditing the internal state of modern electronic gear is difficult-to-impossible. You can audit the communications, and hope you can detect any out-of-spec activity, but that's not easy either.
There's more political maneuvering going on here than any legitimate technical concern.
If anything Russia and China will charge them more than the French now, to "guarantee" there's no backdoor, and since they are in a better negotiation position now than they would've been if UAE reviewed their offers pre-accusing France/US of backdooring the other offer.