Greg, the "save for Web" feature shows you the dimensions and file size of the original and the dimensions and file size of the jpg version, and you can adjust the file size by either changing the dimensions or adjusting the level of jpg compression. You can start with either tif or psd and end up with any size jpg you want. Here is a screen shot of the save for web feature on PSE 2021 which is what you said you are using. I might add that on the current (subscription) version of the full Photoshop the pull down menu is slightly different and this is described as a legacy function....but still works for me.
JBWX
Edited 4 time(s). Last edit at 06/09/2021 01:44PM by John West.