You'll be doing "the latter." Most web browsers these days don't set up home pages except if the user explicitly wants one, and particularly Chromium-based browsers, where reliance on the "On Startup" settings most often take precedence anyway.
Open Chrome settings and search on "Home." The Show Home Button setting will be in the search results, toggled off. If you toggle it on, you will then be presented with two options: New Tab Page (which is what it sounds like you're defaulting to when no Home Page has ever been set at all) and the second radio button is followed by an edit box where you enter the home page you prefer, so you'll select that and enter that.
One note, you do not have to keep the Show Home Button option enabled after you do this, as you will have set a default home page whether or not you choose to have the home button displayed in the collection of browser controls.
After having set a default home page ALT+HOME behaves precisely as you describe it having behaved for you in IE.
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
The purpose of education is not to validate ignorance but to overcome it.