Regarding your threat model, Fedora Workstation sounds like it’d be fine so long as you’re using full-disk encryption with a strong password and keep the laptop powered off when not in use.
As far as I can tell, a lot of devs are fine with (or even prefer) Linux except for when they need to develop for a certain proprietary platform like iOS or macOS which gets tricky on Windows as well. Microsoft Office compatibility is a genuine limitation Microsoft places on non-Windows/Mac users. If neither WinApps nor dual booting Linux with Windows works out for you, you’ll have to switch over to the dark side.
I don’t have personal experience but I do know that people generally don’t recommend it. While the hardware is capable in theory, it sounds like game developers don’t often develop for Apple Silicon Macs. Maybe my knowledge is out of date. For what it’s worth, Linux has great compatibility with Windows games through Proton which is integrated into Steam and can be used for non-Steam games.
Apple is definitely a premium brand, but their repairability seems to me to be some of the worst in the industry. Framework (which officially supports Fedora) is as repairable as a laptop can be and I’ve heard mostly good things about the experience. If that’s not your thing, I’ve heard Dell has a pretty good track record being a more premium brand and they should have some options which officially support Linux. You could ask on a Linux forum or subreddit for better tailored hardware recommendations, they’d be more in the know than I am.
Where there any comments in particular that made you concerned that Linux wouldn’t be suitable for your threat model?
For what it’s worth, Ubuntu’s security (particularly their latest versions) seems mostly comparable to Fedora. The main downside I’ve seen is that Snap forcibly collects some telemetry which is a downside for privacy, but it is still leagues ahead of macOS in that regard and I’d suggest you reconsider it for that reason if Fedora’s community isn’t cutting it for you.
If you’re willing to spend some time on the issue, I’d give WinApps a try to get Microsoft Excel working on Fedora. The mic issue is a matter of asking more active support communities and if that fails, buying a Fedora/Linux supported laptop assuming Excel on WinApps works out for you. Otherwise, I’d give in and get a Mac as a final resort if I were unable or unwilling to get Excel working on Linux.