Those 5 requirements are not small things, but as a (relatively) recent linux migrant, here’s my take.
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Keep using iTunes (but use the windows version) - through wine. You get to keep all your stuff as is for now with the possibility of migrating to another service in the future.
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See above, stick with your current device, keep using iTunes for now.
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If it’s for private stuff LibreOffice suite does just fine though + the thunderbird email client. If it’s for work you should probably have a work device, but there is also winapps for linux, which isn’t official by microsoft, so it might be a bit funky.
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Maybe try out proton if you want something trustworthy to back up your photos. They’ve recently added a service for that. Costs a subscription though.
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Keep using evernote. There’s a linux client.
Obviously there will be hickups, and things’d be a lot more smooth if you were willing to make some adjustments, but this is perfectly doable.
Krita is nice overall, but I have some minor gripes with certain tools behaving unintuitively. May just be because I’m used to GIMP, but some simple stuff such as cropping a layer is not at all convenient.