I have created a seed phrase for Electrum on "Tails" (Linux) and then imported those word phrases into Electrum for Windows before, but I have not done this for a Mac. I presume that the word phrases are not unique to any specific operating system, so you can import it into any Electrum wallet, no matter what OS you are using.
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In some circumstances, it is worth noting the derivation path because even if the seed is the same, the resulting wallet address can differ depending on the wallet type.-snip-
That is, are the electrum of the same version developed for Linux, Windows and MacOS identical. This is not about the security of the OS itself, but specifically about electrum.
As far as I'm aware, the source code is the same regardless of the OS that you use. You can also build and develop it on your own if you don't want to download the app file[1]. Also, they don't use wallet.dat[2] like Bitcoin core. You should be able to copy and paste the wallet file regardless of the OS. CMIIW.[1] https://github.com/spesmilo/electrum#development-version-git-clone
[2] https://electrum.readthedocs.io/en/latest/faq.html#where-is-my-wallet-file-located
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