My recommendations for what they are worth.
Browser: Firefox ESR - the only version that can be locked down if need be.
[uncensored search engine https://mojeek.com I remove Google, Bing, Duck Duck Go, eBay, Yahoo if present. If mojeek doesn't come back with what you are looking for it offers other search engines including Brave search engine.]
E-mail: Evolution. Thunderbird has become too Google centric. When working I could easily access Outlook 365 using Evolution and without any help from IT when in lockdown.
Password manager: I use one of these:
Text Processor: Prior to lockdown I purchased 5 machine licence of SoftMaker Office 2018 and later upgraded to SoftMaker Office 2021 - so much better than MS offerings. You can get the free version Free Office from here:
It is the most compatible with MS Office.
Still yet to try:
Photo Editor: You already get that with Zorin, GIMP.
Music Editor: Not clear what you want to achieve but Audacity 2.2, later versions scrape your data for copyright issues. ZynAddSub FX (https://zynaddsubfx.sourceforge.io/)
MuseScore 3 (Free music composition and notation software | MuseScore)
Media Player: Parole Media Player, SMPlayer, an old but good one Xine.
Zoom ... really? They lied on first launch that connections were encrypted. Once trust has gone you never get it back. Never used it. Use https://meet.jit.si in a browser instead. You can enable encryption, but if you do you can't record the meeting say if using for a training tutorial. Use the Jitsi App for Android.
Games: Most of those come with the OS, apart from bejeweled, you would need to install that.
Turning off Internet is easily done:
The notification area of the taskbar, expand Wireless and select disconnect. If Ethernet connection, Expand Network/Wired and select disconnect.