I am not going to comment on whether your threat model makes sense or whether these protections are necessary, I will just assume you have already thought about this.[1]
How did you apply the MDM profile? Are your devices in Supervised mode? I would not use that as a substitute for Lockdown Mode.
In particular your reasoning to not use Lockdown Mode for convenience reasons doesn’t make sense to me, because you only point out restrictions in Safari as a problem, but Lockdown Mode has the least restrictions on Safari, because you can individually control it per website…
Why do you have two phones? You don’t mention what you do exclusively on your iPhone. I have a similar hardware setup, but each device has a specific purpose, so I just want to make sure you have thought about that. If everything you do on your iPhone can be done on the Pixel, but not everything you do on the Pixel (Signal, 2FA) can be done on the iPhone, then it would make sense to drop the iPhone thereby reducing your attack surface a lot.
What is this “separate MacBook” you mention and is it also a latest generation MacBook? What hardware are you booting your live Linux systems on?
Have you considered running apps like Discord and Telegram in a separate user profile on your Pixel?
I mainly point this out to discourage other people here from commenting on these things even though they do not know you. ↩︎