Do users notice text changes on call to actions?

Brief product Description So I have been working on a digital project where the product is an online presentation software where the user(Teacher) has presentation slides to select and conducts presentations to the students.

Problem The teacher needs to select a presentation slide before heading towards the lobby where the presentation takes place along with other students as you can see on the screens below. The usual process is that the user selects the desired presentation slide and clicks on "continue" and proceeds or the user selects "Continue without presentation slide" where the user gets the default presentation which is a welcome slide.However, the default slide can be changed in the account settings. When the user sets a default slide in the account settings and the slide is not available anymore. The user needs to know that. My initial thoughts were  to change the text on the call to action button from "Continue with Default Presentation"to "Continue without presentation slide(here the default slide would become the welcome slide)". But I am not sure if the user will notice this change or it is better to implement a tooltip like this https://codemyui.com/button-tooltip-hover/ but I think Defaults are used to make the process faster so I think this prolongs the users time. Hence, I think something like this would be more appropriate https://codemyui.com/wonky-rise-css-tooltip-hover/ What do you guyz think? Thank you