I believe even those threads touched many topics(listed below) it does not give you the whole overview so I highly recommend you guys to check out the article that OP mentioned. It is the most comprehensive article criticize Signal I was able to found but if you dig hard you may see some user specific problem on some forums. If we come to my opinion use matrix, run your server with and for your family and friends(I am aware the challenge of convincing them to use such “technically hard to understand” platform but you have to if you care their and your privacy; you have no idea how hard it was for me to convince my wife and teach her)

Funding and Privacy: Some users contend that Signal’s financing sources, such as the Open Technology Fund (OTF), do not jeopardize the company’s privacy features. They point out that the OTF also supports a wide range of other privacy-related technologies, and claim that just because a project receives financing from one source does not imply that the initiative is compromised by that source.

Trade-offs: Signal creates trade-offs that are understandable to the common individual. While some of these trade-offs, such as the necessity of a phone number, may be unappealing to privacy purists, they do make the app more accessible to a wider audience. Some users regard this accessibility as a plus, believing that the benefits of broad encryption exceed the possible privacy problems.

Phone Number Requirement: Some customers are concerned about Signal’s demand for a phone number in order to utilize the service. They contend that this requirement might be used to monitor individuals or connect their identities across sites. Others claim that for most users, who use Signal to connect with people for whom they already have phone numbers, this isn’t an issue.

Centralization and Jurisdiction: Concerns have been raised concerning Signal’s centralized design and its US jurisdiction. Some users believe that these considerations may jeopardize user privacy since the US government may hypothetically compel Signal to send over user data. Others, though, believe that Signal’s end-to-end encryption would restrict the use of any data transferred.

Alternatives: Signal alternatives such as Matrix, Tox, and Jami are examined. These solutions, however, have drawbacks, such as a lack of usability or a smaller user base. Some users say that, while not ideal, these options provide more control and privacy than Signal.

Government Surveillance: Some users say that while Signal is adequate for safeguarding against casual third-party inspection, it may not be the greatest alternative for people who need to protect themselves from government surveillance. They claim that, while Signal’s encryption is excellent, its centralization and jurisdiction in the United States might make it a target for government monitoring attempts.

MobileCoin: The rollout of MobileCoin, a cryptocurrency integrated into Signal, was criticized for being poorly done and communicated. Some users felt that this integration was unnecessary and potentially harmful to Signal’s reputation as a privacy-focused app.

Government: The idea that the US government hasn’t sought to restrict or obstruct Signal because it is happy with the quantity of information it can supply is debatable. Some people find this assertion unsatisfactory and think that further evidence is required. They argue that the absence of action by the US government against Signal might be due to other causes, such as a desire to promote the use of encryption.

Lack of Federation: Signal’s lack of federation is a source of concern. Some users believe Matrix’s case for federation, which would allow multiple servers to speak with one another, is more compelling than Signal’s centralized model. They suggest that federation may provide greater resilience and control than a centralized arrangement.

Hope this was helpful(I know you will continue with whatsapp)