I am not sure about that link with the Kryonaut. MX-4 is good paste, we used to buy it buy the Jar, but when Kryonaut came out after a week of testing, the Delta was so much that I switched us over completely. I am responsible for over 75 business' PC's and Servers, not all of them have been opened up, but every single new PC, or any PC that has had an issue since the client became my client, I test, and always change out the Thermal Paste to Kryonaut. The difference between it and MX4 isn't so huge that you should just stop using MX4, but depending on how hot you run your system it can be the difference of about 5 degrees (we are talking 200watts plus through just the CPU when seeing that kind of difference though.) So if you are comfortable with MX4 then go for it, you really won't notice a difference anyway as long as what you are using is quality paste. That said, I have been using Kryonaut exclusively in my own Rigs and my clients rigs since 2017, and not yet have I had one Thermal Paste related issue. Thats not long enough for me to say that in 5 years you won't have a problem, but I can definitely say that within 2 to 3 years you are highly unlikely to see these quality control issues. Before I had a direct contact at Thermal Grizzly I bought our paste in the 10mL tubes on Amazon, and we go through that about Once a month, some months we went through more, so we had a lot of different packages, and not once I have I seen any type of variance that led to a problem.
Simply put, if you plan on pushing your Ryzen to the absolute max, you want every advantage you can get, and I am 100 Percent confident in saying you will get that from Kryonaut. If you got MX 4 I seriously doubt it would be enough to effect your max sustained frequency, but it could be enough to add a degree or 2 between what you would get with Kryonaut, at the end of the day does that make a difference, probably not, but either way I wouldn't be afraid to use it.
Which ever you choose, between MX 4, NT-H1, or Kryonaut, you will have a good experience.