I think Para. 2. really sums up the rationale for replacing the Duo2.
All the boxes mentioned have good support from ViX and other images ... although I am obviously biased to OpenViX and this forum.
Broadcom vs HiSilicon ... currently I think thats more of a cost issue .. and I have no idea what happens next with the design restrictions imposed by the US government on Huawei (who own HiSilicon), especially with comments in the media that Broadcom may move away from this area (not enough profit margin)..... but if necessary some company will fill the gap.
So I would go with your „gut feelings“ and reap the benefits of the new boxes ... and then its down to your budget, and how much of the extras like large LCD display, FBC tuners, stalker, Kodi are really worth to you... and whether you need them!