I really dislike Flatpak because the humongous sizes of packages. I noticed that Telegram flatpak was 1.1GB in size and requires 3.6GB of the hard drive, whereas the regular DEB install was 28MB and needs only 82 MB.
And there was no DEB available for Signal in the LinuxMint package manager. It also was a 1.1GB download that required 3.6GB of hard drive. Reason there is no Signal app on my desktop.