As someone often on the receiving end of screenshares, I cannot recommend enough that you do not maximize your shared window itself unless it's absolutely necessary. On a typical 15" laptop, 2/3 the width and ¾ the height is great. (for a 4K/5K monitor this will probably be a smaller fraction). Even assuming everyone else has eyesight on par with your own, it's wise to leave room for the chat on one side and a toolbar on the bottom. (And please never maximize a shared window on those 21:9 displays; that is so painful for everyone on a laptop. We get giant black bars at top and bottom, and your text at like 2px.)
People can zoom, yes, but it's going to require scrolling which can be distracting even if it's set to "follow pointer" -- and your pointer may be zipping all over (like, going to the toolbar when the users are looking at a row near the bottom of the screen).
I know it is a challenge to limit yourself to a small canvas -- we all love using a big screen for certain tasks -- but I believe it's going to be easier and make for a more engaging and productive session when you control both the viewport size and the scroll position at all times. One nice thing about Zoom is that it is dynamic, so if you are sharing a window and you realize you need more horizontal real-estate for a certain part of your preso, you can momentarily resize your window for that, and then go back to a more manageable size when done, with no re-sharing needed.