Dropping frames from iPhone footage even after transcoding for CFR
As the title says- I have footage that was shot on an iPhone 6s at "29.97fps" VFR (h.264, not HEVC), which upon import is rendering with up to 7 frames per second missing sporadically (i.e. every nth frame repeats itself x times), depending on what's happening in the footage. I have transcoded the footage into constant frame rate using several different settings combinations in Handbrake (including those recommended by Triem23), yet HitFilm is not only still erratically dropping/duplicating frames, it's dropping so many more with the transcoded files that the resulting imported CFR footage varies from 13-15fps in the render (which is significantly worse than the original non-transcoded VFR .MOV's at 23-30fps, as mentioned; there's even one frame in the transcoded footage that repeats itself 5x in a row.)
More specifically, I've tried transcoding via Handbrake to CFR at 29.97, 30, and "same as source". I used MediaInfo to confirm that the footage was indeed transcoded to the correct frame rate with a Constant status. I have confirmed several times that the HF media timeline settings frame rate is matching up precisely with the frame rate of the media (that includes imported media transcoded to 30fps into a 30fps timeline to avoid the possibility of an inaccurately approximated/oscillating "29.97fps" being exported from HandBrake), and even tried mixing and matching 29.97/30 just to try it, yet the issue persists.
The problem is also not with only with the pre-rendered preview in HF either: I've both rendered within HF and exported the footage, and the problem persists.
I have already watched the video from Triem23 on transcoding, and seen most of CleverTagline's responses on this sort of problem saying that simply transcoding into a constant frame rate will fix this issue. The original .MOV footage and all transcoding combinations I've tried can all be scrubbed frame by frame perfectly within QuickTime, which at least tells me that this footage is all there as MediaInfo and QuickTime Inspector are reporting. I'm under a huge time crunch for this project so is there any way around this or do I just need to bite the bullet, buy Premiere Pro, and ditch HitFilm?
Any help that anyone can provide will be IMMENSELY appreciated!