is it possible to ‘bump’ a blog post?

Yes, with the Adhesive plugin from
https://redalt.com/downloads/

It allows you to mark a post as ‘sticky’ and make it stay at the top.

you could also set the timestamp to a date in the future, but you’d have a goofy looking 2025 date for everyone to see.

how would i change the timestamp?

Access wp-admin, manage. Select the post you wish to change. In the right sidebar is a “timestamp” selection. Click it. Check the box. Change the date, don’t worry about the time. Click the “Save” button to the left under the post entry field.

thanks! might be easier than using that adhesive plugin