This means that the software can evade a virtual machine or a sandboxed application from the host OS, I don't think this is desirable (for me at least).
Of course it may also mean the opposite, it isn't really clear.
In the Control Panel open the Advanced System Options and add the variables and the corresponding paths to the Environmental Variables (for the System if you want them to be used by multiple users).
https://ftp.mozilla.org/pub/firefox/releases/115.30.0esr/win64/en-US/Firefox Setup 115.30.0esr.exe
That's for Firefox ESR 115.30, I couldn't find a Czech version.
If you have Google Messages (you can probably do the same with any other SMS application) you can set sound on for it's notifications and disable the sound for any other notification, if this is what you want. You just have to config the notifications by app.
I have Microsoft Visual C++ 2015 Redistributable (x64) - 14.0.23026 and Microsoft Visual C++ 2015-2022 Redistributable (x86) - 14.30.30704 on Windows 8, I had no problem in installing them.
O&O Shutup Windows 10 helps with the telemetry as far as it can (with Windows 11 doesn't help much due to the lack of telemetry options, which of course doesn't mean the lack of telemetry itself).
Firstly you must check which is the maximum RAM that your processor supports (usually 32 or 64 GB). You can use HWiNFO for this (look at Central Processors>your processor>Memory Ranges>Maximum Physical Address Size.