Is it legal to claim to know approximately how many people died from COVID-19?

[teo123]

Mislav Kolakušić (a Croatian politician, mostly left-wing, except for being a COVID skeptic) has stated multiple times that the only way one can legally claim what somebody died from is if an autopsy has been made. And, he argues, since almost no autopsies have been made on people who supposedly died from COVID-19 (according to him, only one has thus far been done in Croatia), making estimates about how many people died from COVID-19 is illegal. Is that true? I am not sure.
On one hand, how could a law making it illegal to speculate about causes of death exist? Wouldn't it be blatanly unconstitutional?
On the other hand, Mislav Kolakušić studied law. Is it likely that he is wrong about the matters of law? Perhaps a better question is whether it's likely that he is lying.

That's not to say I think official statistics are remotely accurate. Think about this: in almost all countries, the official estimate of how many people died from COVID-19 in 2021, when vaccines were available, is higher than the official estimate of how many people died from COVID-19 in 2020, when no vaccines were available. It seems to me there are only 2 explanations for that:
1. Vaccines are not only ineffective, they are counter-productive. (Which is arguably a conspiracy theory.)
2. The statistics are wildly inaccurate.
And it seems obvious what is more likely.

[teo123]

I think it would be rather interesting to know who is really breaking the law here: COVID skeptics or the people supporting lockdowns and vaccine mandates. Let's discuss it.