Isn't it strange that when you believe in an oligarch, they never disappoint.
Don't put parental controls on it. What do you want to control? Maybe put controls on the website that they can visit, but that goes on the DNS or router. Most kids will go to a mate's house that doesn't have any or as harsh parental controls anyway if they are particularly keen on seeing something that they 'shouldn't'. Parental controls are a fix for parents who can't talk to their kids; they make the parents feel safer but just send the issues underground. Gen X will have been writing code for a while at your child's age. I was. There was no choice if you needed to unlock a game you could've afford. At that time GUIs were a bad overlay over MS-DOS or DR-DOS. You had to know what you were doing to get the best out of it. Your kid will be fine with any distribution of Linux. If your kid is technically inquisitive likely to be good at maths/science, get them installing Arch. If not and they just want to use a browser, install one of the top five popular distributions from distrowatch.com. The Office suite for Linux is called LibreOffice. If you use Chrome as your browser you'll easily tell if your child has been on bad sites because your timeline will be filled with adverts for unsavoury impotence remedies. Enjoy.
PS printers are still bastards in Linux. Happily they're less bastardish in Linux (and Mac, because Linux and iOS use the same printing software) than Windows. If you like your life buy a decent Laser from anyone but HP - my generation bought the last decent HP printers they made.
Zoho mail has a domain hosting platform for email. About £60 pa in dollars for my setup. Pricing varies on the number of accounts not the number if domains. I have two accounts, personal and business, and a control admin account. The domains I host vary according to the businesses I run. I funnel each domains email to one of the two accounts and reply with the appropriate domain easily. Personal email is masked with Addy.io mostly.
They deal with the email very well. There was a time that they really didn't and the system went up and down like a tarts knickers.
The front end is ok. They play with it a lot and there are many screens pushing some shit or other before you actually are allowed to get to the inbox. The inbox setup is excellent with all the expected functionality and toys and many toys appearing monthly.
Typical of Indian continent companies, as a Brit who has spent much of his life frustrated on the phone to "Dave" from Mumbai with a really really thick accent, Zoho don't really seem to understand concepts properly, so their passkeys setup doesn't work with Bitwarden. TOTP 2FA cannot be just pasted in (from Bitwarden again) because they've tried to be flash with the input field and one has to click on a specific place first. The support team try really hard, but their ability to grasp the problem and fix it is lacking before some other buzzword catches marketing's attention and they add yet another screen to click through or subvert the problem somewhere else. Their help knowledge base is enormous, well documented but unorganized and they don't archive stuff that has been superceded, so be careful.
That said I've been using them for well over a decade and have no plans to change.
Running your own mail server ceased to be a hobby thing when RBLs came in. Use a provider with the resources to do the hard/cumbersome stuff.
I'd give Zoho mail an easy 7/10. And it's cheap. Zoho invoice is great too.
If it runs Windows it'll run Linux almost certainly. The cheaper you go, the more likely you'll have lower priced or older components for WiFi, Bluetooth etc which may mean that you have to dig some firmware binaries out to get the whole thing running.
If you can take a USB stick with you of a typical Rescue distribution, and can boot it up, you'll know what will and won't work easily. The bits that don't work may need some minor fiddling. As I said, there are usually walkthrough blogs etc around.
Have fun.
Use your surname with a personal domain. Then you can link up other family members to it. Eg. dave@cammeron.me . Otherwise you've got to have an email address dave@davecammeron.me which looks stupid.
Use your organisation as your work email. boris@megacorp.com, boris.bloke@megacorp.com bb@megacoro.com ceo@megacorp.com
You then separate the work and personal emails. Sending personal emails through a corporate server using the corporate domain is fair game to use in a court, you're ostensibly representing the company and it's not a personal email.
There are various hilarious stories about people losing rights to their name etc post internet era when their company was purchased.
Don't try to run a mail server yourself, that became counter productive about the 2010s. I used to run servers easily last century when there was almost no-one sending email, then the sp-/sc-ammers 'entered the room'.
Accidentally clicking on a wrong email on a unsecure environment can ruin your day if you're tired and just keep clicking mindlessly.
Good luck. Especially if you have a popular surname that your family doesn't own.
For many years I installed Fedora from scratch (almost as if my PC was a Linux container and then added a kernel setup) to be exactly as I wanted it no cruft, no bloat. I did that with other distros as well, Debian didn't recommend SELinux.
Last year I installed it from scratch using the installer and that included SELinux. With changes in SELinux policy, I found an installed flatpak which successive iterations didn't like SELinux or tried to operate outside it. Fixing it was easy but I didn't do so until I understood why it was violating.
I had unknowingly subscribed to the FUD about SELinux, I doesn't get in my way. Maybe I'm not as elite as I thought I was!