As of this AM I can't get GOG manual Update to work, it says Game Install not found no matter where I place the .exe

So I tried to re-download and noticed a discrepancy in the GOG file:

I have a current X4 v3.20 Install (400261).

The X4 Tech Support Forum shows: Current Version and Build Number: 3.30 (406216) - 2020-07-30

But Gog has this Upload: patch_x4_foundations_3.20_(38795)_to_3.30_(39994).exe

And GOG has the full game for Download: setup_x4_foundations_3.30_(64bit)_(39994).exe

I have not had this problem before. If GOG is using different version ID all of a sudden then I will never be able to get the patcher to accept my existing game. Am I going to be forced to complete re-install every time and lose all my progress?

Copy your savegame somewhere else and you are not risking losing progress.

Sorry I only used the Linux files (3.30_40142) and those worked fine but the numbering sure looks odd with the Windows files. A quick message to the correct person and it should be fixed very soon. Sadly I have no clue who that person would be so maybe one of the customer support blues and they can forward it to the correct person or you send in a support ticket and waaaaaaaiiiiit.

Galaxy probably works... I would not know.

Numbers in installer files do not correlate to anything on GOG, AFAIK. Sometimes they include actual game version, but not always.

In order to see actual game version you can look into the "gameinfo" file in the installation directory (on Linux) and ensure it is indeed version 3.30.

But in case of "X4: Foundations" the internal build number is shown in the game's start menu, and it is indeed 406216 (at least in Linux). Excuse me?
I believe, games had stopped storing savefiles in installation directories since somewhere in between "Windows XP" and "Windows Vista" (with introduction of user permissions to the mass Windows audience in the former and "User Account Control" in the later), after they were disallowed to modify the contents of system directories (and the "Program Files" is such).

So, your savefiles are not stored in the game installation directory and its complete removal should be just fine for your games.
In case you wondered, the savegames are stored in the
%USERPROFILE%\Documents\Egosoft\X4\<user-id>\save\
Well, at least according to PC Gaming WIKI: [url=https://www.pcgamingwiki.com/wiki/X4:_Foundations]https://www.pcgamingwiki.com/wiki/X4:_Foundations[/url]