It looks like this is a more general overview for people who don't have any background on this concept, but I have some issues/suggestions.
Step one should be to install GrapheneOS (or if this isn't Android specific, at least mention it). Don't bother with any other ROM, it's the only one that actually takes security seriously [0].
No mention of alternative app stores that don't require a Google account e.g. F-Droid Aurora Store.
No mention of user profiles for isolating apps.
Browser hardening section is fine.. But I think mentioning Bromite would be a good idea. It's a chrome-based browser with privacy protections and ad-block built in [1].
0: https://grapheneos.org/features (list of security features).