Yet again WD Red 4TB FAX vs FRX?

[Quad As]

Hi,
I'm looking closely to Qnap TS-251D populated with a couple of WD Red 4TB HDD based on the following needs:
- Family data storage solution (three persons with individual personal and professional data);
- Multimedia storage and video player through HDMI to the living room TV;
- Own cloud solution for on-the-move access.
My choice for the WD Red was mainly driven by the lower noise level when compared with the Seagate Ironwolf, but considering my complete lack of experience, I'm not sure if that's a significant factor to consider in my case.
Having this WD Red in mind, I've been following the CMR/SMR controversy and all the amazing NASCompares Youtube videos posted to test this novelty from WD. Even watching these videos, I'm still not sure if it pays to buy the new model (FAX), mainly because it is more expensive than the older model (FRX).
Should I go for WD Red FAX, FRX or just go for Seagate (if the noise levels aren't that noticeable)?

[davidjames1701]

I’ve 4 x 3tb frx in my DS 1019+, and have always been solid and reliable, your always going to hear a mechanical hdd, never had a Ironwolf, but I’m tempted at times, specs say they are slightly faster which may mean more noise, but would that be a game changer ? FRX maybe older, but that should mean they are proven technology ? Hope this helps

[Quad As]

My question is mainly about performance. Is it worth going for the new model CMSMR (FAX)?