I'm not sure I understand this comment. I don't know if this suit will really offer protection, but I don't see the problem with the choice of filter.

A HEPA filter has a stricter rating than the N95 masks that healthcare workers use.

"HEPA, which stands for High Efficiency Particulate Air, is a designation used to describe filters that are able to trap 99.97 percent of particles that are 0.3 microns"

N95: Removes 95% of all particles that are at least 0.3 microns in diameter

Yes, HEPA filters are more than sufficient if they genuinely meet these specifications.

The nominal rating is stricter, but is the certification process that the claims of the nominal rating are actually met as strict?

There's what it says it does, and the probability that it actually does what it says it does. Those are two different considerations.

That's a different argument -- whether or not the HEPA filter really is a HEPA filter.

And whether the seal around the HEPA filter that the HEPA filter is put inside is airtight.

E.g. I've seen some vacuum cleaners which have HEPA filters reviewed as a bit useless at filtering because the particles flow through small gaps around the filter.

My mistake.