DJI D-LOG processing in FCP iPad is too saturated

The problem is the lower-end DJI products use D-Log M, not D-Log, and built-in support for D-Log M is limited in NLEs. To my knowledge, neither Premiere Pro, Resolve Studio, nor FCP has that (desktop or iPad versions).

D-Log M is a milder "less flat" profile that is probably more compatible with the 8-bit 4:2:0 encoding used by DJI's lower-end products. The regular D-Log profile uses a flat gamma typical of Sony S-Log3, etc.

In Premiere Pro 25.6.3 desktop, Resolve Studio 20.3.1 and FCP 11.2 (desktop and iPad versions), if you apply the D-Log camera LUT or CST Rec.709 conversion to D-Log M material, it produces an exaggerated, overly vivid result. That is fully expected.

While the desktop versions of Premiere Pro, Resolve and FCP, and iPad versions of FCP and Resolve all lack built-in D-Log M conversion, with iPad Resolve, it's possible to import DJI's D-Log M to Rec.709 conversion LUT and use that. The iPad version of FCP does not currently support third-party LUTs.

I don't know why your Resolve test showed a more normal color result on D-Log M material. I tested it on my M4 iPad Pro and if converting with a Resolve CST from D-Log M to Rec.709, it had the same exaggerated color as FCP. Because D-Log M has a quite mild log curve, it's possible you somehow did not convert it. If you used a third-party D-Log M LUT on your iPad version of Resolve, we would need to know that.

One possible workaround is using DJI's D-Log M LUT in iPad Resolve, converting it and exporting to FCP. Another possibility is using DJI's free DJI Fly app which has built-in D-Log M conversion, then exporting to FCP. The conversion procedure is shown in a Youtube video titled "DJI Mini 5 Pro DLOG M Color Recovery."

Another workaround is using DJI's D-Log M LUT in desktop FCP, converting it there then exporting to iPad FCP.

To review, this situation is not limited to iPad FCP. There is no built-in support for DJI's D-Log M in any of the main NLEs. I don't know why. You have to convert D-Log M using a third-party LUT or an external utility. It is nice that iPad Resolve supports third-party LUTs. You could request that future versions of FCP on iPadOS add third-party LUT support: Feedback - Final Cut Pro - Apple

Forgot to add, you can also grade D-Log M manually, without a conversion LUT. If you search for "How to Color Grade Drone Footage in Final Cut Pro The Easy Way" that tutorial shows one basic approach. It is easier to grade D-Log M manually than regular D-Log. This works on the iPad or desktop version of Final Cut Pro.